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469705 ǂKá̦gára
469705 ǂKá̦gára (provisional designation 2005 EF298) is a trans-Neptunian object and binary system of the core Kuiper belt, located in the outermost region of the Solar System. It was discovered on 11 March 2005 by American astronomer Marc Buie at the Kitt Peak Observatory in Arizona. [1] The primary body measures around 140 kilometers (90 miles) in diameter. Its 120-kilometer (75-mile) companion ǃHãunu was discovered with the Hubble Space Telescope in 2009. The ǂKá̦gára–ǃHãunu system is currently undergoing mutual occultation and eclipsing events in which one body casts a shadow on or obstructs the view of the other as seen from Earth.
469705 ǂKá̦gára
Stacked Hubble Space Telescope images of ǂKá̦gára and ǃHãunu
Discovery[1]
Discovered byMarc Buie
Discovery siteKitt Peak Observatory
Discovery date11 March 2005
Designations
MPC designation
(469705) ǂKá̦gára
Pronunciation
• English: /ˈkɑːʔɡɑːrə/
• ǀXam: [ǂ͡káˤɡáɾa]
Named after
ǂKá̦gára (San mythology)[2]
Alternative designations
2005 EF298
Minor planet category
Cold classical KBO[2]
Orbital characteristics[3][1]
Epoch (JD 2458600.5)
Uncertainty parameter 3
Observation arc10.10 yr (3688 d)
Aphelion44.058 AU
Perihelion40.013 AU
Semi-major axis
44.081 AU
Eccentricity0.085
Orbital period (sidereal)
292.45 yr (106744.25 d)
Mean anomaly
118.059°
Mean motion
0.00337 0° 0m 0s / day
Inclination1.60°
Longitude of ascending node
118.059°
Argument of perihelion
77.966°
Known satellites1[4]
Physical characteristics
Mean diameter
138+21
−25 km, assuming same albedo as ǃHãunu
Mass(1.29±0.07)×1018 kg, assuming same density and albedo as ǃHãunu
Mean density
1.1+0.9
−0.4 g/cm3, assuming equal compositions of the bodies
Absolute magnitude (H)
HV = 6.2±0.5
Names
The names ǂKá̦gára and ǃHãunu are from the mythology of the ǀXam people of South Africa. ǂKá̦gára (also rendered ǂKaʻgara) and his brother-in-law ǃHãunu fought an epic battle in the east using thunder and lightning, producing mountainous clouds and rain. The conflict was fought over ǂKá̦gára's returning his younger sister, ǃHãunu's wife, to their parents. [2][5] The names were approved and an official naming citation was published on 16 June 2021 by the International Astronomical Union's Working Group on Small Body Nomenclature. [6]
In the ǀXam language, ǂKá̦gára and ǃHãunu are thought to have been pronounced [ǂ͡káˤɡáɾa] [Note 1] and [ᵑ̊ǃʰəunu] ,[Note 2] respectively. [7] The initial letters ǂK and !H (and indeed the letter ǀX in 'ǀXam') represent some of the many click consonants that characterize ǀXam and other San languages. The diacritic under the first vowel in ǂKá̦gára indicates that it is a pharyngealized vowel, another characteristic of San languages. When pronounced in English, the click consonants in words from ǀXam and other San languages are usually ignored (much as Xhosa is pronounced /ˈkoʊzə/ (KOH-zə) rather than [ǁʰosa]), resulting in /ˈkɑːʔɡɑːrə/ (KAHʼ-gar-ə) and /ˈhaʊnuː/ (HOW-noo). ASCII approximations of the names are =Ka'gara and !Haunu.
Orbit and occultations
ǂKá̦gára is a cold classical Kuiper belt object. It orbits the Sun at a distance of 44 AU once every 290 years. Its orbit has an eccentricity of 0.09 and an inclination of 3 degrees with respect to the ecliptic. [3]
If the two bodies are spheres with equal density, then mutual occultation events between ǂKá̦gára and its satellite ǃHãunu should have begun in 2015 and should continue until 2035. When ǂKá̦gára passes in front of ǃHãunu, events may last as long as 8 hours, but when ǃHãunu passes in front of ǂKá̦gára they are expected to last as long as 2 days. These latter events are only expected to occur from 2022 to 2027. [2]
Formation
Prograde orbits dominate tight binary systems such as 469705 ǂKá̦gára, those with satellite semimajor axes less than about 5% of their Hill radii. Grundy et al. suggest that this could be "the signature of planetesimal formation through gravitational collapse of local density enhancements such as caused by the streaming instability",[2] which has been suggested as the formative mechanism of the only visited planetesimal, 486958 Arrokoth.
Satellite, size and mass
ǃHãunu
Discovery
Discovery date2009
Designations
Pronunciation
• English: /ˈhaʊnuː/
• ǀXam: [ᵑ̊ǃʰəunu]
Named after
ǃHãunu (San mythology)[2]
Alternative names
• ǂKá̦gára I
• S/2009 (469705) 1
Orbital characteristics[2][8][4]
Semi-major axis
7670±140 km
Eccentricity0.694±0.013
Orbital period (sidereal)
128.107±0.027 d (prograde)
Inclination
• 33.33°±0.41° ref'd to J2000 equatorial frame
• 11.17°±0.41° to heliocentric orbit
Physical characteristics
Mean diameter
122+16
−19 km , assuming same albedo as ǂKá̦gára
Mass(0.89±0.05)×1018 kg, assuming same density and albedo as ǂKá̦gára
Apparent magnitude
ΔH = 0.59
469705 ǂKá̦gára has one known satellite, ǃHãunu. The magnitude difference between ǂKá̦gára and ǃHãunu is 0.59 mag. This corresponds to a difference in diameter of 13%, if the two bodies have the same albedo. [2]
The system mass is (2.18±0.12)×1018 kg, and, given the albedo, the bodies are equivalent to a single sphere of diameter 174+27
−32 km . This corresponds to a density of 1.1+0.9
−0.4 g/cm3 . This does not particularly constrain the composition of the bodies, as the error bars cover the densities of both small, porous bodies and larger, collapsed bodies. Assuming the two bodies have the same albedo and density, their masses are (1.29±0.07)×1018 kg and (0.89±0.05)×1018 kg, and their diameters are 138+21
−25 km and 122+16
−19 km . [2]
Notes
1. Bleek & Lloyd wrote ⟨ǂk⟩ when the posterior release of the click was audible. | 0 | 0 |
Based on the sounds attested in the closely related language Nǁng, this [ǂ͡k] may therefore represent a palatal pulmonic-contour click, though this is not certain.
2. Based on the co-occurrence of the letter ⟨H⟩ for aspiration of the click and the tilde for nasalization on the following vowel, together with the patterns of sounds in Nǁng, it is suspected that the click in ǃHãunu has delayed aspiration (i.e., is a long, aspirated, nasalized click), rather than a simple IPA: [ǃʰə̃unu], though again this is not certain.
References
1. "469705 (2005 EF298)". Minor Planet Center. Retrieved 7 April 2019.
2. Grundy, W.M. ; Noll, K.S. ; Roe, H.G. ; Buie, M.W. ; Porter, S.B. ; Parker, A.H.; Nesvorný, D.; Levison, H.F.; Benecchi, S.D. ; Stephens, D.C.; Trujillo, C.A. (April 2019). "Mutual orbit orientations of transneptunian binaries". Icarus. 334: 62–78. doi:10.1016/j.icarus.2019.03.035. Retrieved 6 April 2019. (heliocentric parameters averaged over 10Myr)
3. "JPL Small-Body Database Browser: 469705 (2005 EF298)" (2015-04-06 last obs.). Jet Propulsion Laboratory. Retrieved 7 April 2019.
4. Johnston, Wm. Robert (27 May 2019). "Asteroids with Satellites Database – (469705) 2005 EF298". Johnston's Archive. Retrieved 18 June 2021.
5. ≠kagara's fight with !haunu in the east. Lucy Lloyd |xam notebooks, vol. VIII-30, July 1879.
6. "WGSBN Bulletin" (PDF), Working Group Small Body Nomenclature, vol. 1, no. 3, p. 15, 16 June 2021
7. Will Grundy: 469705 (how to say)
8. "ǂKá̦gára and ǃHãunu (469705 2005 EF298)". Mutual Orbits of Binary Transneptunian Objects. Retrieved 7 April 2019. (heliocentric parameters averaged over 10Myr)
External links
• Asteroids with Satellites, Johnston's Archive
• List of Known Trans-Neptunian Objects, Johnston's Archive
• List of Transneptunian Objects, Minor Planet Center
• 469705 ǂKá̦gára at the JPL Small-Body Database
• 469705 ǂKá̦gára at AstDyS-2, Asteroids—Dynamic Site
• Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
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• 469705 ǂKá̦gára
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(111253) 2001 XU10
(111253) 2001 XU10 (provisional designation 2001 XU10) is an asteroid on an eccentric orbit, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 3 kilometers in diameter. It was discovered on 9 December 2001, by astronomers of the LINEAR program at Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States. [2] The asteroid is one of the largest potentially hazardous asteroids. [4]
(111253) 2001 XU10
Discovery[1]
Discovered byLINEAR
Discovery siteLincoln Lab's ETS
Discovery date9 December 2001
Designations
MPC designation
(111253) 2001 XU10
Alternative designations
2001 XU10
Minor planet category
Apollo · NEO · PHA[1][2]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc17.94 yr (6,552 days)
Aphelion2.5242 AU
Perihelion0.9832 AU
Semi-major axis
1.7537 AU
Eccentricity0.4394
Orbital period (sidereal)
2.32 yr (848 days)
Mean anomaly
38.733°
Mean motion
0° 25m 27.84s / day
Inclination42.020°
Longitude of ascending node
310.17°
Argument of perihelion
6.9341°
Earth MOID0.0293 AU · 11.4 LD
Physical characteristics
Dimensions3.006±0.893 km[3]
Geometric albedo
0.178±0.156[3]
Absolute magnitude (H)
15.2[1]
Orbit and classification
2001 XU10 orbits the Sun at a distance of 0.98–2.52 AU once every 2 years and 4 months (848 days; semi-major axis of 1.75 AU). Its orbit has an eccentricity of 0.44 and an inclination of 42° with respect to the ecliptic. [1] The body's observation arc begins with a precovery taken by the Sloan Digital Sky Survey in February 2000. [2]
2001 XU10 is a member of the Apollo asteroids, the largest subgroup of near-Earth asteroids which cross the orbit of Earth. It is also a Mars-crosser, as it crosses the orbit of the Red Planet at 1.66 AU. [1]
Close approaches
With an absolute magnitude of 15.2, 2001 XU10 is one of the brightest and presumably largest known potentially hazardous asteroid. [4] It has an Earth minimum orbital intersection distance of 0.0293 AU (4,380,000 km), which translates into 11.4 lunar distances (LD). [1] On 29 July 2054, this asteroid will make its closest near-Earth encounter of the 21st century at a nominal distance of 0.079 AU (31.1 LD). [1]
Physical characteristics
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 2001 XU10 measures 3.006 kilometers in diameter and its surface has an albedo of 0.178. [3]
As of 2018, no rotational lightcurve of 2001 XU10 has been obtained from photometric observations. The asteroid's rotation period, spin axis and shape remain unknown. In addition, the body's spectral type has never been assessed. [1][5]
Numbering and naming
This minor planet was numbered by the Minor Planet Center on 19 October 2005. [6] As of 2018, it has not been named. [2]
References
1. "JPL Small-Body Database Browser: 111253 (2001 XU10)" (2018-01-16 last obs.). Jet Propulsion Laboratory. Retrieved 19 January 2018.
2. "111253 (2001 XU10)". Minor Planet Center. Retrieved 19 January 2018.
3. Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Cutri, R. M.; McMillan, R. S.; et al. (November 2012). "Physical Parameters of Asteroids Estimated from the WISE 3-Band Data and NEOWISE Post-Cryogenic Survey". The Astrophysical Journal Letters. 760 (1): 6. arXiv:1210.0502. Bibcode:2012ApJ...760L..12M. doi:10.1088/2041-8205/760/1/L12.
4. "List of the Potentially Hazardous Asteroids (PHAs)". Minor Planet Center. Retrieved 19 January 2018.
5. "LCDB Data for (111253)". Asteroid Lightcurve Database (LCDB). Retrieved 19 January 2018.
6. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 February 2018.
External links
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• (111253) 2001 XU10 at NeoDyS-2, Near Earth Objects—Dynamic Site
• Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• (111253) 2001 XU10 at ESA–space situational awareness
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• (111253) 2001 XU10 at the JPL Small-Body Database
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11351 Leucus
11351 Leucus /ˈljuːkəs/ is a mid-sized Jupiter trojan from the Greek camp, approximately 40 kilometers (25 miles) in diameter. It is a target of the Lucy mission, scheduled for a flyby in April 2028. [8][10] The assumed D-type asteroid is an exceptionally slow rotator with a rotation period of 466 hours. [3] It was discovered on 12 October 1997 by the Beijing Schmidt CCD Asteroid Program (SCAP) at Xinglong Station in the Chinese province of Hebei, and later named after the Achaean warrior Leucus from Greek mythology. [1]
11351 Leucus
Shape model of Leucus viewed from multiple orthogonal perspectives
Discovery[1]
Discovered bySCAP
Discovery siteBeijing Xinglong Obs.
Discovery date12 October 1997
Designations
MPC designation
(11351) Leucus
Pronunciation/ˈljuːkəs/[2]
Named after
Leucus (Greek mythology)[1]
Alternative designations
1997 TS25 · 1996 VP39
Minor planet category
Jupiter trojan[1][3]
Greek[4] · background[5]
Orbital characteristics[3]
Epoch 25 February 2023 (JD 2460000.5)
Uncertainty parameter 0
Earliest precovery date25 July 1982[1]
Aphelion5.652 AU
Perihelion4.953 AU
Semi-major axis
5.302 AU
Eccentricity0.0659
Orbital period (sidereal)
12.21 yr (4,460 d)
Mean anomaly
43.784°
Mean motion
0° 4m 50.607s / day
Inclination11.546°
Longitude of ascending node
251.087°
Argument of perihelion
160.955°
Jupiter MOID0.0942 AU
TJupiter2.955
Physical characteristics
Dimensions63.8 × 36.6 × 29.6 km[6]
Mean diameter
41 km (volume equivalent)[6]
Synodic rotation period
445.683±0.007 h[7][3]
Axial tilt
13° (wrt ecliptic)[7]
10° (wrt orbit)[7]
Pole ecliptic latitude
+77°[7]
Pole ecliptic longitude
208°[7]
Geometric albedo
0.037±0.001[6]
Spectral type
D[8]
B–V = 0.739±0.044[9]
V–R = 0.498±0.044[9]
V–I = 0.900±0.057[9]
Absolute magnitude (H)
10.979±0.037[7]
Orbit and classification
Leucus is a dark Jupiter trojan asteroid in a 1:1 orbital resonance with Jupiter. It is located in the leading Greek camp at Jupiter's L4 Lagrangian point, 60° ahead of its orbit (see Trojans in astronomy). It is also a non-family asteroid in the Jovian background population. [5]
It orbits the Sun at a distance of 5.0–5.6 AU once every 12 years and 2 months (4,440 days; semi-major axis of 5.29 AU). Its orbit has an eccentricity of 0.06 and an inclination of 12° with respect to the ecliptic. [3] The body's observation arc begins with a precovery taken at the Siding Spring Observatory in July 1982, more than 15 years prior to its official discovery observation at Xinglong. [1]
Exploration
Lucy mission target
Leucus is planned to be visited by the Lucy spacecraft, which launched in 2021. The flyby is scheduled for 18 April 2028, and will approach the asteroid to a distance of 1,000 km (620 mi) at a relative velocity of 5.9 km/s (13,000 mph). [8]
Physical characteristics
Leucus is a D-type asteroid,[8] which is the dominant spectral type among the Jupiter trojans, with the remainder being mostly carbonaceous C-type and primitive P-type asteroids.
Slow rotator
During spring 2013, a rotational lightcurve of Leucus was obtained from photometric observations made by astronomers Robert Stephens and Daniel Coley at the Center for Solar System Studies (CS3), California, using a 0.35/0.4-meter Schmidt-Cassegrain telescope. The lightcurve showed an exceptionally slow rotation period of 513.7 hours with a brightness variation of 0.53 in magnitude (U=2+). No evidence of a non-principal axis rotation (NPAR) was found. [11] It is one of the slowest rotators known to exist.
In preparation for the planned visit by the Lucy spacecraft, Leucus was once again observed by astronomers Marc Buie at SwRI and Stefano Mottola at DLR in 2016. The obtained bimodal lightcurve gave a somewhat shorter period of 440 hours and an amplitude of 0.7 magnitude. [12]
Diameter and albedo
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Leucus has a low albedo of 0.06 and 0.08, with a diameter of 42.1 and 34.2 kilometers, respectively. [13][14] The Collaborative Asteroid Lightcurve Link derives a lower albedo of 0.05 and a diameter of 42.1 kilometers, in accordance with the result obtained by IRAS. [15]
Naming
This minor planet was named from Greek mythology, after the Achaean warrior Leucus in Homer's Iliad. He was a companion of Odysseus. [1] Leucus was killed during the Trojan War by Antiphus, one of the fifty sons of King Priam of Troy. [16] The approved naming citation was published by the Minor Planet Center on 22 February 2016 (M.P.C. 98711). [17]
References
1. "11351 Leucus (1997 TS25)". Minor Planet Center. Retrieved 22 June 2018.
2. Noah Webster (1884) A Practical Dictionary of the English Language
3. "JPL Small-Body Database Browser: 11351 Leucus (1997 TS25)" (2017-06-07 last obs.). Jet Propulsion Laboratory. Retrieved 22 June 2018.
4. "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. Retrieved 22 June 2018.
5. "Asteroid (11351) Leucus – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 22 June 2018.
6. Buie, Marc W.; Keeney, Brian A.; Strauss, Ryder A.; Blank, Ted E.; Moore, John G.; Porter, Simon B. (October 2021). "Size and Shape of (11351) Leucus from Five Occultations". The Planetary Science Journal. 2 (5): 38. Bibcode:2021PSJ.....2..202B. doi:10.3847/PSJ/ac1f9b. S2CID 237623594. 202.
7. Mottola, Stefano; Hellmich, Stephan; Buie, Marc W.; Zangari, Amanda M.; Marchi, Simone; Brown, Michael E.; Levison, Harold F. (December 2020). "Convex Shape and Rotation Model of Lucy Target (11351) Leucus from Lightcurves and Occultations". The Planetary Science Journal. 1 (3): 14. arXiv:2009.08951. Bibcode:2020PSJ.....1...73M. doi:10.3847/PSJ/abb942. S2CID 221802440. 73.
8. Levison, H. F.; Olkin, C.; Noll, K. S.; Marchi, S.; Lucy Team (March 2017). "Lucy: Surveying the Diversity of the Trojan Asteroids: The Fossils of Planet Formation" (PDF). 48th Lunar and Planetary Science Conference (1964): 2025. Bibcode:2017LPI....48.2025L. Retrieved 13 April 2017.
9. Hainaut, O. R.; Boehnhardt, H.; Protopapa, S. (October 2012). "Colours of minor bodies in the outer solar system. II. A statistical analysis revisited". Astronomy and Astrophysics. 546: 20. arXiv:1209.1896. Bibcode:2012A&A...546A.115H. doi:10.1051/0004-6361/201219566. | 2 | 0 |
S2CID 54776793.
10. Casey Dreier; Emily Lakdawalla (30 September 2015). "NASA announces five Discovery proposals selected for further study". The Planetary Society. Retrieved 12 April 2017.
11. French, Linda M.; Stephens, Robert, D.; Coley, Daniel R.; Wasserman, Lawrence H.; Vilas, Faith; La Rocca, Daniel (October 2013). "A Troop of Trojans: Photometry of 24 Jovian Trojan Asteroids". The Minor Planet Bulletin. 40 (4): 198–203. Bibcode:2013MPBu...40..198F. ISSN 1052-8091. {{cite journal}}: CS1 maint: multiple names: authors list (link)
12. Buie, Marc W.; Zangari, Amanda Marie; Marchi, Simone; Mottola, Stefano; Levison, Harold F. (October 2016). "Ground-based characterization of Leucus and Polymele, two fly-by targets of the Lucy Discovery mission". American Astronomical Society. 48: 208.06. Bibcode:2016DPS....4820806B.
13. Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. arXiv:1209.1549. Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. S2CID 119101711. (online catalog)
14. Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 15 June 2018.
15. "LCDB Data for (11351) Leucus". Asteroid Lightcurve Database (LCDB). Retrieved 22 June 2018.
16. Homer, Iliad, 4. 491
17. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 22 June 2018.
External links
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Discovery Circumstances: Numbered Minor Planets (10001)-(15000) – Minor Planet Center
• Asteroid 11351 Leucus at the Small Bodies Data Ferret
• 11351 Leucus at AstDyS-2, Asteroids—Dynamic Site
• Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 11351 Leucus at the JPL Small-Body Database
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• 11350 Teresa
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• 11352 Koldewey
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(11474) 1982 SM2
(11474) 1982 SM2 is a carbonaceous Baptistina asteroid and potentially slow rotator from the inner regions of the asteroid belt, approximately 6 kilometers in diameter. It was discovered on 18 September 1982, by Belgian astronomer Henri Debehogne at ESO' La Silla Observatory in northern Chile. [5]
(11474) 1982 SM2
Discovery[1]
Discovered byH. Debehogne
Discovery siteLa Silla Obs.
Discovery date18 September 1982
Designations
MPC designation
(11474) 1982 SM2
Alternative designations
1982 SM2 · 1995 KD
Minor planet category
main-belt · Baptistina[2]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc32.59 yr (11,905 days)
Aphelion2.7224 AU
Perihelion1.8294 AU
Semi-major axis
2.2759 AU
Eccentricity0.1962
Orbital period (sidereal)
3.43 yr (1,254 days)
Mean anomaly
76.029°
Mean motion
0° 17m 13.56s / day
Inclination5.4069°
Longitude of ascending node
348.59°
Argument of perihelion
355.61°
Physical characteristics
Dimensions5.71 km (calculated)[2]
Synodic rotation period
1917.2214±2716 h[3]
Geometric albedo
0.057 (assumed)[2]
Spectral type
C[2]
Absolute magnitude (H)
14.493±0.001 (R)[3] · 14.7[1] · 14.94[2] · 14.94±0.61[4]
Orbit and classification
The C-type asteroid belongs to the small Baptistina family. It orbits the Sun at a distance of 1.8–2.7 AU once every 3 years and 5 months (1,254 days). Its orbit has an eccentricity of 0.20 and an inclination of 5° with respect to the ecliptic. [1] As no precoveries were taken, and no prior identifications were made, the asteroid's observation arc begins with its official discovery observation. [5]
Physical characteristics
In September 2013, a rotational lightcurve of this asteroid was obtained from photometric observations in the R-band at the Palomar Transient Factory in California. It gave an exceptionally long rotation period of 1917 hours with a brightness amplitude of 0.04 magnitude (U=1). [3] However, the fragmentary light-curve has received a low quality rating by the Collaborative Asteroid Lightcurve Link (CALL) which means that the result could be completely wrong (also see potentially slow rotator). [2][3]
CALL assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 5.71 kilometers, based on an absolute magnitude of 14.49. [2]
Numbering and naming
This minor planet was numbered by the Minor Planet Center on 28 September 1999. [6] As of 2018, it has not been named. [5]
References
1. "JPL Small-Body Database Browser: 11474 (1982 SM2)" (2015-04-23 last obs.). Jet Propulsion Laboratory. Retrieved 26 May 2017.
2. "LCDB Data for (11474)". Asteroid Lightcurve Database (LCDB). Retrieved 16 December 2016.
3. Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. S2CID 8342929. Retrieved 16 December 2016.
4. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. S2CID 53493339. Retrieved 16 December 2016.
5. "11474 (1982 SM2)". Minor Planet Center. Retrieved 16 December 2016.
6. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 February 2018.
External links
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (10001)-(15000) – Minor Planet Center
• (11474) 1982 SM2 at AstDyS-2, Asteroids—Dynamic Site
• Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• (11474) 1982 SM2 at the JPL Small-Body Database
Minor planets navigator
• 11473 Barbaresco
• (11474) 1982 SM2
• 11475 Velinský
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(118228) 1996 TQ66
(118228) 1996 TQ66 (provisional designation 1996 TQ66) is a resonant trans-Neptunian object of the plutino population in the Kuiper belt, located in the outermost region of the Solar System. It was discovered on 8 October 1996, by American astronomers Jun Chen, David Jewitt, Chad Trujillo, and Jane Luu, using the UH88 telescope at the Mauna Kea Observatories, Hawaii. [1][2] The very red object measures approximately 185 kilometers (110 miles) in diameter. As of 2021, it has not been named.
(118228) 1996 TQ66
Discovery[1][2]
Discovered byJ. Chen
D. C. Jewitt
C. Trujillo
J. X. Luu
Discovery siteMauna Kea Obs.
Discovery date8 October 1996
Designations
MPC designation
(118228) 1996 TQ66
Alternative designations
1996 TQ66
Minor planet category
TNO[3] · plutino[4][5]
Orbital characteristics[3]
Epoch 1 July 2021 (JD 2459396.5)
Uncertainty parameter 2
Observation arc24.17 yr (8,828 d)
Aphelion44.219 AU
Perihelion34.535 AU
Semi-major axis
39.377 AU
Eccentricity0.1230
Orbital period (sidereal)
247.10 yr (90,254 d)
Mean anomaly
33.659°
Mean motion
0° 0m 14.4s / day
Inclination14.650°
Longitude of ascending node
10.613°
Argument of perihelion
18.541°
Physical characteristics
Mean diameter
185 km (est. at 0.09)[4]
Spectral type
• RR (very red)[6][7]
• B–V = 1.190±0.020[6]
• V–R = 0.660±0.030[6]
• V–I = 1.440±0.140[6]
Apparent magnitude
22.85[8]
Absolute magnitude (H)
7.14[2][3]
Orbit and classification
1996 TQ66 orbits the Sun at a distance of 34.5–44.2 AU once every 247 years and 1 month (90,254 days; semi-major axis of 39.38 AU). Its orbit has an eccentricity of 0.12 and an inclination of 15° with respect to the ecliptic. [3] The body's observation arc begins with its official discovery observation at the Mauna Kea Observatories on 8 October 1996. [2] It came to perihelion in 1998. As of 2021, it is at 35.6 AU from the Sun and has an apparent magnitude of 22.85. [8]
1996 TQ66 is a trans-Neptunian object and belongs to the plutino population,[4][5] a large group of objects named after their largest member, Pluto. These resonant trans-Neptunian objects stay in a 2:3 mean-motion orbital resonance with Neptune, orbiting exactly two times the Sun for every three orbits Neptune does and are therefore protected from Neptune's scattering effect. Plutinos are located in the inner rim of the Kuiper belt, a large circumstellar disc of mostly non-resonant classical Kuiper belt objects.
Numbering and naming
1996 TQ66 was numbered by the Minor Planet Center on 16 November 2005, receiving the number (118228) in the minor planet catalog (M.P.C. 55524). [9] As of 2021, it has not been named. [2] According to the established naming conventions, it will be given a mythological name associated with the underworld. [10]
Physical characteristics
1996 TQ66 has a very red surface color (RR) in the visible part of the spectrum, with B−V and V–R color indices of 1.190±0.020 and 0.660±0.030, respectively, for a combined B−R magnitude of 1.85. [4][6][7] A red surface color is typically associated with the presence of tholins, polymer-like organic compounds, formed by long exposures to solar and cosmic radiation.
Rotation period
In 1999, results of a photometric survey of Kuiper belt objects by Romanishin and Tegler were published in the Journal Nature. For 1996 TQ66, a brightness variation of no more than 0.22 in magnitude could be determined, which is indicative of a modestly irregular shape. [7][11] As of 2021, no rotational lightcurve for this object has been obtained from photometry. The body's rotation period, pole and actual shape remain unknown. [3][7]
Diameter and albedo
Based on a generic magnitude-to-diameter conversion, 1996 TQ66 measures approximately 185 kilometers (110 miles) in diameter, for an assumed albedo of 0.9 and an magnitude of 7. [4][12] According to Mike Brown, who estimates a mean-diameter of 186 km (120 mi), the object is too small for being considered a dwarf planet candidate ("probably not"). [13]
References
1. "MPEC 1997-N09 : 1996 TQ66". Minor Planet Electronic Circular. Minor Planet Center. 7 July 1997. Retrieved 9 September 2021.
2. "118228 (1996 TQ66)". Minor Planet Center. Retrieved 10 September 2021.
3. "JPL Small-Body Database Browser: 118228 (1996 TQ66)" (2020-12-09 last obs.). Jet Propulsion Laboratory. Retrieved 10 September 2021.
4. "List of Known Trans-Neptunian Objects". Johnston's Archive. 18 August 2020. Retrieved 10 September 2021.
5. "Orbit Fit and Astrometric record for 118228". Southwest Research Institute. Retrieved 10 September 2021.
6. Belskaya, Irina N.; Barucci, Maria A.; Fulchignoni, Marcello; Dovgopol, Anatolij N. (April 2015). "Updated taxonomy of trans-neptunian objects and centaurs: Influence of albedo". Icarus. 250: 482–491. Bibcode:2015Icar..250..482B. doi:10.1016/j.icarus.2014.12.004. ISSN 0019-1035.
7. "LCDB Data for (118228)". Asteroid Lightcurve Database (LCDB). Retrieved 10 September 2021.
8. "Asteroid (118228) 1996 TQ66 – Ephemerides". AstDyS-2, Asteroids – Dynamic Site. Retrieved 10 September 2021.
9. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 10 September 2021.
10. "Naming of Astronomical Objects – Minor planets". IAU – International Astronomical Union. Retrieved 27 July 2021.
11. Romanishin, W.; Tegler, S. C. (March 1999). "Rotation rates of Kuiper-belt objects from their light curves". Nature. 398 (6723): 129–132. Bibcode:1999Natur.398..129R. doi:10.1038/18168. ISSN 0028-0836. S2CID 4313184.
12. "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 10 September 2021.
13. Brown, Michael E. "How many dwarf planets are there in the outer solar system?". California Institute of Technology. Retrieved 10 September 2021.
External links
• MPEC 1997-N20 : 1996 TQ66, Minor Planet Electronic Circular
• (118228) 1996 TQ66, Small Bodies Data Ferret
• Kuiper Belt Object Magnitudes and Surface Colors, Stephen C. Tegler (archived)
• List of Transneptunian Objects, Minor Planet Center
• Discovery Circumstances: Numbered Minor Planets (115001)–(120000), Minor Planet Center
• (118228) 1996 TQ66 at AstDyS-2, Asteroids—Dynamic Site
• Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• (118228) 1996 TQ66 at the JPL Small-Body Database
Trans-Neptunian objects
TNO classes | 4 | 0 |
• Cubewanos
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• Vanth
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• Haumea
• Namaka
• Hiʻiaka
• Ring
• Quaoar
• Weywot
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• Makemake
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• Gonggong
• Xiangliu
• Eris
• Dysnomia
• Sedna
Sednoids
• 90377 Sedna
• 2012 VP113
• 541132 Leleākūhonua
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• (118228) 1996 TQ 66
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(118378) 1999 HT11
(118378) 1999 HT11 (provisional designation 1999 HT11) is a trans-Neptunian object from the outermost region of the Solar System, locked in a 4:7 orbital resonance with Neptune. It was discovered on 17 April 1999, by astronomers at the Kitt Peak Observatory, Arizona, in the United States. [2] The very red object measures approximately 134 kilometers (83 miles) in diameter. As of 2021, it has not been named.
(118378) 1999 HT11
Discovery[1][2]
Discovered byKitt Peak National Obs.
Discovery siteKitt Peak National Obs.
Discovery date17 April 1999
Designations
MPC designation
(118378) 1999 HT11
Alternative designations
1999 HT11
Minor planet category
TNO[3] · res (4:7)[4][5]
Orbital characteristics[3]
Epoch 1 July 2021 (JD 2459396.5)
Uncertainty parameter 3[2][3]
Observation arc20.78 yr (7,589 d)
Aphelion49.001 AU
Perihelion38.734 AU
Semi-major axis
43.868 AU
Eccentricity0.1170
Orbital period (sidereal)
290.55 yr (106,124 d)
Mean anomaly
328.33°
Mean motion
0° 0m 12.24s / day
Inclination5.0489°
Longitude of ascending node
87.954°
Argument of perihelion
189.27°
Physical characteristics
Mean diameter
134 km (est. at 0.09)[4]
Spectral type
• RR (very red)[4]
• B–V = 1.150±0.064[6][7]
• V–R = 0.670±0.040[6][7]
• B–R = 1.820±0.050[6][7]
Apparent magnitude
23.42[8]
Absolute magnitude (H)
7.6[2][3]
Discovery
1999 HT11 was first observed on the night of 17 April 1999, by astronomers using the 4-meter Nicholas U. Mayall Telescope at Kitt Peak National Observatory in Arizona. Five additional objects were discovered on the same weekend: 1999 HR11, 1999 HS11, 1999 HU11 (Deucalion), 1999 HV11 and 1999 HW11. The observing astronomers were Robert Millis, James Elliot, Matthew Holman, Mark Wagner as well as Kim Falinski. Follow-up observations with the Nordic Optical Telescope at the Roque de los Muchachos Observatory, La Palma, Spain, were made three weeks later. The body's observation arc begins with its official discovery observation at Kitt Peak on 17 April 1999. [1][2]
Orbit and classification
This minor planet orbits the Sun at a distance of 38.7–49.0 AU once every 290 years and 7 months (106,124 days; semi-major axis of 43.87 AU). Its orbit has an eccentricity of 0.12 and an inclination of 5° with respect to the ecliptic. [3] As of 2021, it is at 39.7 AU from the Sun with an apparent magnitude of 23.42,[8] and will come to perihelion in 2047. [3]
1999 HT11 is a resonant trans-Neptunian object that stays in a 4:7 mean-motion orbital resonance with Neptune, orbiting exactly four times the Sun for every seven orbits Neptune does and are therefore protected from the planets scattering effect. The classification is deemed secure. [4][5] The 4:7 resonance is located in the midst of the classical objects of the Kuiper belt, a circumstellar disc of otherwise non-resonant bodies, contrary to the more prominent resonant plutinos (2:3) and twotinos (1:2) which form the inner and outer rim of the Kuiper belt, respectively.
Numbering and naming
This minor planet was numbered by the Minor Planet Center on 16 November 2005, receiving the number (118378) in the minor planet catalog (M.P.C. 55526). [9] As of 2021, it has not been named. [2] According to the established naming conventions, it will be given a mythological name associated with the underworld or with creation. [10]
Physical characteristics
1999 HT11 has a very red surface color (RR) in the visible part of the spectrum, with B−V and V–R color indices of 1.150±0.064 and 0.670±0.040, respectively, for a combined B−R magnitude of 1.820±0.050. [4][6][7] A red surface color is typically associated with the presence of tholins, polymer-like organic compounds, formed by long exposures to solar and cosmic radiation.
Based on a generic magnitude-to-diameter conversion, 1999 HT11 measures approximately 134 kilometers (83 miles) in diameter, for an assumed albedo of 0.9 and an magnitude of 7.6. [4][11] According to Mike Brown, who estimates a mean-diameter of 137 km (85 mi), the object is too small for being considered a dwarf planet candidate ("probably not"). [12] As of 2021, no rotational lightcurve for this body has been obtained from photometric observations. Its rotation period, pole and shape remain unknown. [3]
References
1. "MPEC 1999-K12 : SIX TNOs (including J99H11T)". Minor Planet Electronic Circular. Minor Planet Center. 19 May 1999. Retrieved 9 September 2021.
2. "118378 (1999 HT11)". Minor Planet Center. Retrieved 11 September 2021.
3. "JPL Small-Body Database Browser: 118378 (1999 HT11)" (2020-01-26 last obs.). Jet Propulsion Laboratory. Retrieved 11 September 2021.
4. "List of Known Trans-Neptunian Objects". Johnston's Archive. 18 August 2020. Retrieved 11 September 2021.
5. "Orbit Fit and Astrometric record for 118378". Southwest Research Institute. Retrieved 11 September 2021. (The Deep Ecliptic Survey Object Classifications)
6. Sheppard, Scott S. (December 2012). "The Color Differences of Kuiper Belt Objects in Resonance with Neptune". The Astronomical Journal. 144 (6): 169. arXiv:1210.0537. Bibcode:2012AJ....144..169S. doi:10.1088/0004-6256/144/6/169. ISSN 0004-6256. S2CID 53746049.
7. "LCDB Data for (118378)". Asteroid Lightcurve Database (LCDB). Retrieved 11 September 2021.
8. "Asteroid (118378) 1999 HT11 – Ephemerides". AstDyS-2, Asteroids – Dynamic Site. Retrieved 11 September 2021.
9. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 11 September 2021.
10. "Naming of Astronomical Objects – Minor planets". IAU – International Astronomical Union. Retrieved 11 September 2021.
11. "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 11 September 2021.
12. Brown, Michael E. "How many dwarf planets are there in the outer solar system?". California Institute of Technology. Retrieved 11 September 2021.
External links
• List of Transneptunian Objects, Minor Planet Center
• (118378) 1999 HT11, Small Bodies Data Ferret
• Discovery Circumstances: Numbered Minor Planets (115001)-(120000), Minor Planet Center
• (118378) 1999 HT11 at AstDyS-2, Asteroids—Dynamic Site
• Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• (118378) 1999 HT11 at the JPL Small-Body Database
Trans-Neptunian objects
TNO classes
• Cubewanos
• Scattered-disc objects
• Detached objects
• Resonant objects
• Neptune trojans
• Plutinos
• Twotinos
• TNO moons
Dwarf planets (moons)
• Orcus
• Vanth
• Pluto
• Charon
• Styx
• Nix
• Kerberos
• Hydra
• Haumea
• Namaka | 5 | 0 |
• Hiʻiaka
• Ring
• Quaoar
• Weywot
• Rings
• Makemake
• MK2
• Gonggong
• Xiangliu
• Eris
• Dysnomia
• Sedna
Sednoids
• 90377 Sedna
• 2012 VP113
• 541132 Leleākūhonua
• 2021 RR205
Minor planets navigator
• (118378) 1999 HT 11
• (118379) 1999 HC12
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121 Hermione
Hermione (minor planet designation: 121 Hermione) is a very large binary asteroid discovered in 1872. It orbits in the Cybele group in the far outer asteroid belt. [11] As an asteroid of the dark C spectral type, it is probably composed of carbonaceous materials. In 2002, a small moon was found to be orbiting Hermione. [11]
121 Hermione
121 Hermione and its moon
Discovery[1]
Discovered byJames Craig Watson
Discovery date12 May 1872
Designations
MPC designation
(121) Hermione
Pronunciation/hɜːrˈmaɪ.əniː/[2]
Named after
Hermione[3]
(Greek mythology)
Alternative designations
A872 JA; 1970 VE
Minor planet category
main-belt · Cybele
AdjectivesHermionean /hɜːrmaɪ.əˈniːən/
Orbital characteristics[4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc145.96 yr (53,312 d)
Aphelion3.9067 AU
Perihelion2.9889 AU
Semi-major axis
3.4478 AU
Eccentricity0.1331
Orbital period (sidereal)
6.40 yr (2,338 d)
Mean anomaly
157.08°
Mean motion
0° 9m 14.4s / day
Inclination7.5975°
Longitude of ascending node
73.127°
Argument of perihelion
298.18°
Known satellitesS/2002 (121) 1
Physical characteristics
Dimensions268 × 186 × 183 km[5]
(254 ± 4) × (125 ± 9) km[6]
Mean radius
95 km[6]
Volume(3.0±0.4)×106 km3[7]
Mass(5.381±5%)×1018 kg[7]
Mean density
1.8 ± 0.2 g/cm3[7][lower-alpha 1]
Equatorial surface gravity
0.022 m/s2[lower-alpha 2]
Equatorial escape velocity
0.075 km/s[lower-alpha 2]
Sidereal rotation period
0.2313 d (5.551 h)[8]
Axial tilt
73°
Pole ecliptic latitude
+10 ± 2°[7]
Pole ecliptic longitude
1.5 ± 2°
Geometric albedo
0.0482 ± 0.002[9]
Spectral type
C[10]
Absolute magnitude (H)
7.31[9]
Discovery
Hermione was discovered by J. C. Watson on 12 May 1872 from Ann Arbor, Michigan, in the United States,[11] and named after Hermione, daughter of Menelaus and Helen in Greek mythology. [3]
Physical properties
The asteroid has a bi-lobed shape, as evidenced by adaptive optics images, the first of which were taken in December 2003 with the Keck telescope. [6] Of several proposed shape models that agreed with the images, a "snowman"-like shape was found to best fit the observed precession rate of Hermione's satellite. [7] In this "snowman" model, the asteroid's shape can be approximated by two partially overlapping spheres of radii 80 and 60 km, whose centers are separated by a distance of 115 km. A simple ellipsoid shape was ruled out.
Observation of the satellite's orbit has made possible an accurate determination of Hermione's mass. [7] For the best-fit "snowman" model, the density is found to be 1.8 ± 0.2 g/cm3, giving a porosity on the order of 20%, and possibly indicating that the main components are fractured solid bodies, rather than the asteroid being a rubble pile.
Occultations by Hermione have been successfully observed three times so far, the last time in February 2004.
S/2002 (121) 1
Discovery[12]
Discovered byW. J. Merline,
P. M. Tamblyn,
C. Dumas,
L. M. Close,
C. R. Chapman,
F. Menard,
W. M. Owen,
and D. C. Slater
Discovery date2002-09-28
Designations
Alternative designations
LaFayette
Minor planet category
main-belt · Cybele
Orbital characteristics[13]
Semi-major axis
768 ± 11 km
Eccentricity0.001 ± 0.001
Orbital period (sidereal)
2.582 ± 0.002 d
Inclination3 ± 2°
(with respect to Hermione pole)
Satellite of121 Hermione
Physical characteristics
Dimensions12 ± 4 km[6]
Mass~1.6×1015 kg[lower-alpha 3]
Absolute magnitude (H)
13.0[6]
Moon
A satellite of Hermione was discovered in 2002 with the Keck II telescope. [11] It is about 8 miles (13 km) in diameter. [11] The satellite is provisionally designated S/2002 (121) 1. It has not yet been officially named, but "LaFayette" has been proposed by a group of astronomers in reference to the frigate used in secret by the Marquis de Lafayette to reach America to help the insurgents. [14][6]
Notes
1. Using the "snowman" shape model, which best matches the value of J2 implied from precession.
2. On the extremities of the long axis.
3. Assuming a similar density to the primary.
References
1. "121 Hermione". Minor Planet Center. Retrieved 14 September 2018.
2. Noah Webster (1884) A Practical Dictionary of the English Language
3. Schmadel, Lutz D. (2007). "(121) Hermione". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 26. doi:10.1007/978-3-540-29925-7_122. ISBN 978-3-540-00238-3.
4. "JPL Small-Body Database Browser: 121 Hermione" (2018-05-25 last obs.). Jet Propulsion Laboratory. Retrieved 14 September 2018.
5. Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 2 July 2013. Retrieved 7 December 2008.
6. F. Marchis; et al. (2006). "Shape, size and multiplicity of main-belt asteroids I. Keck Adaptive Optics survey". Icarus. 185 (1): 39–63. Bibcode:2006Icar..185...39M. doi:10.1016/j.icarus.2006.06.001. PMC 2600456. PMID 19081813.
7. F. Marchis; et al. (2005). "Mass and density of Asteroid 121 Hermione from an analysis of its companion orbit". Icarus. 178 (2): 450–464. Bibcode:2005Icar..178..450M. doi:10.1016/j.icarus.2005.05.003.
8. IAUC 8264 Archived 9 July 2008 at the Wayback Machine
9. Supplemental IRAS minor planet survey Archived 2009-08-17 at the Wayback Machine
10. PDS node taxonomy database Archived 2009-08-05 at the Wayback Machine
11. Linda T. Elkins-Tanton (2010). Asteroids, Meteorites, and Comets. Infobase Publishing. p. 96. ISBN 978-1-4381-3186-3.
12. IAUC 7980 Archived 2006-05-01 at the Wayback Machine
13. 121 Hermione and S/2002 (121) 1, orbit data website maintained by F. Marchis.
14. Johnston, Wm. Robert (21 September 2014). "(121) Hermione and S/2002 (121) 1 ("LaFayette")". Asteroids with Satellites Database. Johnston's Archive. Retrieved 7 November 2021.
External links
• 121 Hermione and S/2002 (121) 1, orbit data website maintained by F. Marchis. Includes adaptive optics images, orbit diagrams, and shape models.
• (121) Hermione, datasheet, johnstonsarchive.net
• Asteroids with Satellites, Robert Johnston, johnstonsarchive.net | 6 | 0 |
• Tally of Asteroids Harboring Moons Grows Beyond 30 (Space.com, 3 October 2002)
• 121 Hermione at AstDyS-2, Asteroids—Dynamic Site
• Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 121 Hermione at the JPL Small-Body Database
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(126154) 2001 YH140
(126154) 2001 YH140 (provisional designation 2001 YH140) is a resonant trans-Neptunian object discovered on 18 December 2001, by American astronomers Chad Trujillo and Michael Brown at the Palomar Observatory in California. It measures approximately 345 kilometers in diameter. [4]
(126154) 2001 YH140
Discovery
Discovered byMichael E. Brown,
Chadwick A. Trujillo[1]
Discovery date18 December 2001
Designations
MPC designation
(126154) 2001 YH140
Minor planet category
TNO (3:5 resonance)[2]
Orbital characteristics[1][3]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 2
Observation arc4777 days (13.08 yr)
Aphelion48.725 AU (7.2892 Tm)
Perihelion36.428 AU (5.4496 Tm)
Semi-major axis
42.577 AU (6.3694 Tm)
Eccentricity0.14441
Orbital period (sidereal)
277.82 yr (101475 d)
Mean anomaly
19.455°
Mean motion
0° 0m 12.772s / day
Inclination11.069°
Longitude of ascending node
108.84°
Argument of perihelion
356.62°
Physical characteristics
Dimensions345 ± 45 km[4]
Mass~4.0×1019 kg
Synodic rotation period
13.25 h (0.552 d)
Sidereal rotation period
13.25 ± 0.2 h[5]
Geometric albedo
0.06–0.10[4]
Temperature~42 K
Absolute magnitude (H)
5.8,[4] 5.5[3]
Orbit and rotation
2001 YH140 is locked in 3:5 mean-motion resonance with Neptune. [4] When it makes three revolutions around the Sun, Neptune makes exactly five. The rotation period of (126154) 2001 YH140 is estimated to be 13.25 ± 0.2 hours. [5]
Physical characteristics
In 2010 thermal flux from (126154) 2001 YH140 in the far-infrared was measured by the Herschel Space Telescope. As a result, its size has been estimated to be 300–390 km (190–240 mi). [4]
References
1. "List Of Transneptunian Objects". IAU Minor Planet Center. Retrieved 2011-01-08.
2. "MPEC 2009-R09 :Distant Minor Planets (16 September 2009.0 TT)". IAU Minor Planet Center. 2009-09-04. Retrieved 2009-10-04.
3. "JPL Small-Body Database Browser: (126154) 2001 YH140" (last obs). 2009-02-02. Retrieved 11 April 2016.
4. Müller, T. G.; Lellouch, E.; Stansberry, J.; Kiss, C.; Santos-Sanz, P.; Vilenius, E.; Protopapa, S.; Moreno, R.; Mueller, M.; Delsanti, A.; Duffard, R.; Fornasier, S.; Groussin, O.; Harris, A. W.; Henry, F.; Horner, J.; Lacerda, P.; Lim, T.; Mommert, M.; Ortiz, J. L.; Rengel, M.; Thirouin, A.; Trilling, D.; Barucci, A.; Crovisier, J.; Doressoundiram, A.; Dotto, E.; Gutiérrez, P. J.; Hainaut, O. R.; Hartogh, P. (July–August 2010). ""TNOs are Cool": A survey of the trans-Neptunian region". Astronomy and Astrophysics. 518: L146. arXiv:1005.2923. Bibcode:2010A&A...518L.146M. doi:10.1051/0004-6361/201014683. S2CID 118635387.
5. Sheppard, Scott S. (August 2007). "Light Curves of Dwarf Plutonian Planets and other Large Kuiper Belt Objects: Their Rotations, Phase Functions, and Absolute Magnitudes". The Astronomical Journal. 134 (2): 787–798. arXiv:0704.1636. Bibcode:2007AJ....134..787S. doi:10.1086/519072. S2CID 56247384.
External links
• (126154) 2001 YH140 at the JPL Small-Body Database
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(126155) 2001 YJ140
(126155) 2001 YJ140 (provisional designation 2001 YJ140) is a resonant trans-Neptunian object from the outermost regions of the Solar System, approximately 154 kilometers in diameter. It discovered on 20 December 2001, by American astronomers Chad Trujillo, Glenn Smith and Michael E. Brown at the Palomar Observatory in California. [1]
(126154) 2001 YJ140
Discovery
Discovered byM. E. Brown
C. Trujillo
Glenn Smith
Discovery sitePalomar Obs.
Discovery date20 December 2001
Designations
MPC designation
(126155) 2001 YJ140
Alternative designations
none
Minor planet category
TNO · plutino
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 3
Observation arc2455 days (6.72 yr)
Aphelion51.307 AU (7.6754 Tm)
Perihelion27.906 AU (4.1747 Tm)
Semi-major axis
39.606 AU (5.9250 Tm)
Eccentricity0.29542
Orbital period (sidereal)
249.26 yr (91043.2 d)
Mean anomaly
10.650°
Mean motion
0° 0m 14.235s / day
Inclination5.9691°
Longitude of ascending node
319.51°
Argument of perihelion
129.91°
Physical characteristics
Dimensions154 km (Johnston's Archive)
Absolute magnitude (H)
7.3
Orbit and rotation
2001 YJ140 is classified as a plutino, a large class of objects in a 2:3 orbital resonance with Neptune. Its orbit has a semi-major axis of 42.396 AU and an orbital period of about 249 years. Perihelion leads to 27.881 AU from the Sun and its aphelion in the distance of 51.348 AU. [2][3]
References
1. "JPL Small-Body Database Browser: 126155 (2001 YJ140)". NASA/Jet Propulsion Laboratory. Retrieved 7 April 2016.
2. MPEC 2009-R09 : DISTANT MINOR PLANETS (2009 SEPT. 16.0 TT)
3. List Of Transneptunian Objects
Sources
• NASA.gov
• IAU Minor Planet Center
External links
• (126155) 2001 YJ140 at AstDyS-2, Asteroids—Dynamic Site
• Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• (126155) 2001 YJ140 at the JPL Small-Body Database
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• (126154) 2001 YH140
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(131696) 2001 XT254
(131696) 2001 XT254, provisionally known as 2001 XT254, is a Kuiper belt object (KBO)[2] that has a 3:7 resonance with Neptune. [3]
(131696) 2001 XT254
Discovery[1]
Discovered bySheppard, S. S., Kleyna, J., Jewitt, D. C.
Discovery date9 December 2001
Designations
MPC designation
(131696) 2001 XT254
Minor planet category
SDO[2]
3:7 resonance[3][4]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 3
Observation arc4113 days (11.26 yr)
Aphelion70.889 AU (10.6048 Tm) (Q)
Perihelion35.892 AU (5.3694 Tm) (q)
Semi-major axis
53.391 AU (7.9872 Tm) (a)
Eccentricity0.32774 (e)
Orbital period (sidereal)
390.13 yr (142494 d)
Mean anomaly
359.98° (M)
Mean motion
0° 0m 9.095s / day (n)
Inclination0.51687° (i)
Longitude of ascending node
359.55° (Ω)
Argument of perihelion
133.36° (ω)
Earth MOID34.907 AU (5.2220 Tm)
Jupiter MOID30.5705 AU (4.57328 Tm)
Physical characteristics
Dimensions146 km (assumed)[5]
Geometric albedo
0.09 (assumed)
Absolute magnitude (H)
7.4[1]
It will come to perihelion in January 2016. [1]
Assuming a generic TNO albedo of 0.09, it is about 146 km in diameter. [5]
Resonance
Simulations by Emel’yanenko and Kiseleva in 2007 show that (131696) 2001 XT254 is librating in a 3:7 resonance with Neptune. [6] This libration can be stable for less than 100 million to billions of years. [6]
It has been observed 22 times over 4 oppositions. [1]
See also
(95625) 2002 GX32 has a similar resonant behavior.
References
1. "JPL Small-Body Database Browser: 131696 (2001 XT254)" (2006-01-29 last obs). Retrieved 7 April 2016.
2. "List Of Centaurs and Scattered-Disk Objects". Minor Planet Center. Retrieved 2009-01-30.
3. Marc W. Buie. "Orbit Fit and Astrometric record for 131696" (2013-03-24 using 28 observations). SwRI (Space Science Department). Retrieved 2009-01-30.
4. "MPEC 2009-A63 :Distant Minor Planets (2009 JAN. 29.0 TT)". Minor Planet Center. 2009-01-13. Retrieved 2009-01-30.
5. Wm. Robert Johnston (22 August 2008). "List of Known Trans-Neptunian Objects". Johnston's Archive. Archived from the original on 13 February 2009. Retrieved 2009-01-30.
6. Emel’yanenko, V. V; Kiseleva, E. L. (2008). "Resonant motion of trans-Neptunian objects in high-eccentricity orbits". Astronomy Letters. 34 (4): 271–279. Bibcode:2008AstL...34..271E. doi:10.1134/S1063773708040075. S2CID 122634598.
External links
• (131696) 2001 XT254 at the JPL Small-Body Database
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• (131696) 2001 XT254
• (131697) 2001 XH255
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(131697) 2001 XH255
(131697) 2001 XH255, provisionally known as 2001 XH255, is a trans-Neptunian object (TNO) that has a 4:5 resonance with Neptune. [2]
(131697) 2001 XH255
Discovery[1]
Discovered by
• Kleyna, J.
• Sheppard, S. S.
• Jewitt, D. C.
Discovery date11 December 2001
Designations
MPC designation
(131697) 2001 XH255
Minor planet category
• TNO
• 4:5 resonance[2][3]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 3
Observation arc4110 days (11.25 yr)
Aphelion37.907 AU (5.6708 Tm) (Q)
Perihelion32.339 AU (4.8378 Tm) (q)
Semi-major axis
35.123 AU (5.2543 Tm) (a)
Eccentricity0.079253 (e)
Orbital period (sidereal)
208.16 yr (76030.5 d)
Mean anomaly
318.51° (M)
Mean motion
0° 0m 17.046s / day (n)
Inclination2.8512° (i)
Longitude of ascending node
323.17° (Ω)
Argument of perihelion
217.87° (ω)
Earth MOID31.3433 AU (4.68889 Tm)
Jupiter MOID26.8986 AU (4.02397 Tm)
Physical characteristics
Dimensions100 km (assumed)[4]
Geometric albedo
0.09 (assumed)
Apparent magnitude
23.6[5]
Absolute magnitude (H)
8.2[1]
It will come to perihelion in 2041. [1]
Assuming a generic TNO albedo of 0.09, it is about 100 km in diameter. [4]
Resonance
According to the Deep Ecliptic Survey and Minor Planet Center, (131697) 2001 XH255 has a 4:5 resonance with Neptune. [2][3] It comes as close as 32.2 AU from the Sun and has a fairly low orbital eccentricity of 0.07 with an inclination of only 2.86 degrees. [1]
The Neptune 4:5 resonance keeps it more than 7 AU from Neptune over a 14000-year period. [6]
It has been observed 21 times over 5 oppositions and has an orbit quality code of 3. [1]
Potential for Exploration
A NASA study in 2019 that confirmed the viability of using small radioisotope or nuclear fission power systems combined with xenon electric propulsion for deep space exploration, used 2001 XH255 as a representative Kuiper Belt Object as the mission's destination to orbit. [7]
References
1. "JPL Small-Body Database Browser: 131697 (2001 XH255)" (last observation: 2006-01-29). Retrieved 7 April 2016.
2. Marc W. Buie. "Orbit Fit and Astrometric record for 131697" (2006-01-29 using 19 observations). SwRI (Space Science Department). Retrieved 1 February 2009.
3. "MPEC 2009-A63 :Distant Minor Planets (2009 JAN. 29.0 TT)". Minor Planet Center. 13 January 2009. Retrieved 1 February 2009.
4. Wm. Robert Johnston (22 August 2008). "List of Known Trans-Neptunian Objects". Johnston's Archive. Archived from the original on 13 February 2009. Retrieved 1 February 2009.
5. "AstDys (131697) 2001XH255 Ephemerides". Department of Mathematics, University of Pisa, Italy. Archived from the original on 26 May 2011. Retrieved 16 March 2009.
6. "MPEC 2006-H30 : 2001 XT254, 2001 XH255". Minor Planet Center. 22 April 2006. Retrieved 1 February 2009.
7. Oleson, S.; et al. (19 August 2019). "A Kuiper Belt Object Orbiter Enabled By 10 kW Kilopower Electric Propulsion" (PDF). NASA NTRS. Archived (PDF) from the original on 19 March 2020.
External links
• (131697) 2001 XH255 at the JPL Small-Body Database
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• (131697) 2001 XH255
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(13366) 1998 US24
(13366) 1998 US24 (provisional designation 1998 US24) is a Jupiter trojan from the Greek camp, approximately 33 kilometers (21 miles) in diameter. It was discovered on 18 October 1998, by astronomers with the Lowell Observatory Near-Earth-Object Search at the Anderson Mesa Station near Flagstaff, Arizona, in the United States. [1] The dark Jovian asteroid is a slow rotator with a long rotation period of potentially 400 hours. [7] It has not been named since its numbering in January 2000. [8]
(13366) 1998 US24
Discovery[1]
Discovered byLONEOS
Discovery siteAnderson Mesa
Discovery date18 October 1998
Designations
MPC designation
(13366) 1998 US24
Alternative designations
1998 US24 · 1996 RX29
Minor planet category
Jupiter trojan[1][2]
Greek[3] · background[4]
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc64.27 yr (23,476 d)
Aphelion5.7685 AU
Perihelion4.6895 AU
Semi-major axis
5.2290 AU
Eccentricity0.1032
Orbital period (sidereal)
11.96 yr (4,367 d)
Mean anomaly
193.23°
Mean motion
0° 4m 56.64s / day
Inclination6.6365°
Longitude of ascending node
96.296°
Argument of perihelion
355.47°
Jupiter MOID0.3771 AU
TJupiter2.9760
Physical characteristics
Mean diameter
33.30±2.87 km[5]
Synodic rotation period
400±105 h[6]
Geometric albedo
0.058±0.016[5]
Spectral type
C (assumed)[7]
Absolute magnitude (H)
11.10[5]
11.2[1][7]
11.3[2]
Orbit and classification
1998 US24 is a dark Jovian asteroid in a 1:1 orbital resonance with Jupiter. It is located in the leading Greek camp at the Gas Giant's L4 Lagrangian point, 60° ahead of its orbit (see Trojans in astronomy). [3] It is also a non-family asteroid in the Jovian background population. [4] It orbits the Sun at a distance of 4.7–5.8 AU once every 11 years and 12 months (4,367 days; semi-major axis of 5.23 AU). Its orbit has an eccentricity of 0.10 and an inclination of 7° with respect to the ecliptic. [2] The body's observation arc begins with a precovery taken at Palomar Observatory in February 1954, more than 44 years prior to its official discovery observation at Anderson Mesa. [1]
Numbering and naming
This minor planet was numbered by the MPC on 24 January 2000 (M.P.C. 37586). [8] As of 2018, it has not been named. [1]
Physical characteristics
1998 US24 is an assumed C-type asteroid, while most larger Jupiter trojans are D-types. [7]
Rotation period
In August 2015, a first rotational lightcurve of 1998 US24 was obtained from photometric observations by the Kepler space telescope during its K2 mission. Lightcurve analysis gave a rotation period of 400±105 hours with a brightness variation of 0.23 magnitude (U=2-). [6] One month later, a second, lower-rated lightcurve by Kepler determined an alternative period of 522±36 hours with an amplitude of 0.20 (U=1+). [9] As of 2018, no secure period of this slow rotator has yet been obtained. [7]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 1998 US24 measures 33.30 kilometers in diameter and its surface has an albedo of 0.058,[5] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 32.03 kilometers based on an absolute magnitude of 11.2. [7]
100+ largest Jupiter trojans
Largest Jupiter Trojans by survey(A)
(mean-diameter in kilometers; YoD: Year of Discovery)
Designation H WISE IRAS Akari Ln RP V–I YoD Ref
624 Hektor7.2225233230.99L46.920.9301907list
617 Patroclus8.19140.362140.92140.85L5102.800.8301906list
911 Agamemnon7.89131.038166.66185.30L46.590.9801919list
588 Achilles8.67130.099135.47133.22L47.310.9401906list
3451 Mentor8.4126.288116.30117.91L57.700.7701984list
3317 Paris8.3118.790116.26120.45L57.090.9501984list
1867 Deiphobus8.3118.220122.67131.31L558.660.9301971list
1172 Äneas8.33118.020142.82148.66L58.710.9501930list
1437 Diomedes8.3117.786164.31172.60L424.490.8101937list
1143 Odysseus7.93114.624125.64130.81L410.110.8601930list
2241 Alcathous8.64113.682114.63118.87L57.690.9401979list
659 Nestor8.99112.320108.87107.06L415.980.7901908list
3793 Leonteus8.7112.04686.2687.58L45.620.7801985list
3063 Makhaon8.4111.655116.14114.34L48.640.8301983list
1583 Antilochus8.6108.842101.62111.69L431.540.9501950list
884 Priamus8.81101.09396.29119.99L56.860.9001917list
1208 Troilus8.99100.477103.34111.36L556.170.7401931list
1173 Anchises8.8999.549126.27120.49L511.600.7801930list
2207 Antenor8.8997.65885.1191.32L57.970.9501977list
2363 Cebriones9.1195.97681.8484.61L520.050.9101977list
4063 Euforbo8.795.619102.46106.38L48.850.9501989list
2357 Phereclos8.9494.62594.9098.45L514.390.9601981list
4709 Ennomos8.591.43380.8580.03L512.280.6901988list
2797 Teucer8.789.430111.14113.99L410.150.9201981list
2920 Automedon8.888.574111.01113.11L410.210.9501981list
15436 Dexius9.187.64685.7178.63L48.970.8701998list
3596 Meriones9.287.38075.0973.28L412.960.8301985list
2893 Peiroos9.2386.88487.4686.76L58.960.9501975list
4086 Podalirius9.185.49586.8985.98L410.430.8701985list
4060 Deipylos9.384.04379.2186.79L49.300.7601987list
1404 Ajax9.383.99081.6996.34L429.380.9601936list
4348 Poulydamas9.582.03270.0887.51L59.910.8401988list
5144 Achates9.080.95891.9189.85L55.960.9201991list
4833 Meges8.980.16587.3389.39L414.250.9401989list | 11 | 0 |
2223 Sarpedon9.4177.48094.63108.21L522.740.8801977list
4489 Dracius9.076.59592.9395.02L412.580.9501988list
2260 Neoptolemus9.3176.43571.6581.28L48.180.9501975list
5254 Ulysses9.276.14778.3480.00L428.720.9701986list
3708 Socus9.375.66179.5976.75L56.550.9801974list
2674 Pandarus9.174.26798.10101.72L58.481.0001982list
3564 Talthybius9.473.73068.9274.11L440.590.9001985list
4834 Thoas9.172.33186.8296.21L418.190.9501989list
7641 Cteatus9.471.83968.9775.28L427.770.9801986list
3540 Protesilaos9.370.22576.8487.66L48.950.9401973list
11395 Iphinous9.868.97764.7167.78L417.38–1998list
4035 Thestor9.668.73368.2366.99L413.470.9701986list
5264 Telephus9.468.47273.2681.38L49.530.9701991list
1868 Thersites9.568.16370.0878.89L410.480.9601960list
9799 Thronium9.668.03364.8772.42L421.520.9101996list
4068 Menestheus9.567.62562.3768.46L414.400.9501973list
23135 Pheidas9.966.23058.2968.50L48.690.8602000list
2456 Palamedes9.365.91691.6699.60L47.240.9201966list
3709 Polypoites9.165.29799.0985.23L410.041.0001985list
1749 Telamon9.564.89881.0669.14L416.980.9701949list
3548 Eurybates9.663.88572.1468.40L48.710.7301973list
4543 Phoinix9.763.83662.7969.54L438.871.2001989list
12444 Prothoon9.863.83564.3162.41L515.82–1996list
4836 Medon9.563.27767.7378.70L49.820.9201989list
16070 Charops9.763.19164.1368.98L520.240.9601999list
15440 Eioneus9.662.51966.4871.88L421.430.9701998list
4715 Medesicaste9.762.09763.9165.93L58.810.8501989list
34746 Thoon9.861.68460.5163.63L519.630.9502001list
38050 Bias9.861.60361.0450.44L418.850.9901998list
5130 Ilioneus9.760.71159.4052.49L514.770.9601989list
5027 Androgeos9.659.78657.86n.a.L411.380.9101988list
6090 Aulis9.459.56874.5381.92L418.480.9801989list
5648 Axius9.759.29563.91n.a.L537.560.9001990list
7119 Hiera9.759.15076.4077.29L44000.9501989list
4805 Asteropaios10.057.64753.1643.44L512.37–1990list
16974 Iphthime9.857.34155.4357.15L478.90.9601998list
4867 Polites9.857.25158.2964.29L511.241.0101989list
2895 Memnon10.056.70655.67n.a.L57.500.7101981list
4708 Polydoros9.954.96455.67n.a.L57.520.9601988list
(21601) 1998 XO8910.054.90955.6756.08L412.650.9701998list
12929 Periboea9.954.07761.0455.34L59.270.8801999list
17492 Hippasos10.053.97555.67n.a.L517.75–1991list
5652 Amphimachus10.153.92153.1652.48L48.371.0501992list
2759 Idomeneus9.953.67661.0152.55L432.380.9101980list
5258 Rhoeo10.253.27550.77n.a.L419.851.0101989list
(12126) 1999 RM1110.153.202n.a.n.a.L5n.a. ?1999list
(15502) 1999 NV2710.053.10055.6750.86L515.130.8751999list
4754 Panthoos10.053.02553.1556.96L527.68–1977list
4832 Palinurus10.052.05853.16n.a.L55.321.0001988list
5126 Achaemenides10.551.92244.2248.57L453.02–1989list
3240 Laocoon10.251.69550.77n.a.L511.310.8801978list
4902 Thessandrus9.851.26361.0471.79L47380.9601989list
11552 Boucolion10.151.13653.1653.91L532.44–1993list
(20729) 1999 XS14310.450.96146.30n.a.L45.721.0001999list
6545 Leitus10.150.95153.16n.a.L416.260.9101986list
4792 Lykaon10.150.87053.16n.a.L540.090.9601988list
21900 Orus10.050.81055.6753.87L413.450.9501999list
1873 Agenor10.150.79953.7654.38L520.60–1971list
5028 Halaesus10.250.77050.77n.a.L424.940.9001988list
2146 Stentor9.950.75558.29n.a.L416.40–1976list
4722 Agelaos10.050.37853.1659.47L518.440.9101977list
5284 Orsilocus10.150.15953.16n.a.L410.310.9701989list
11509 Thersilochos10.149.96053.1656.23L517.37–1990list
5285 Krethon10.149.60658.5352.61L412.041.0901989list
4791 Iphidamas10.149.52857.8559.96L59.701.0301988list
9023 Mnesthus10.149.15150.7760.80L530.66–1988list
5283 Pyrrhus9.748.35664.5869.93L47.320.9501989list
4946 Askalaphus10.248.20952.7166.10L422.730.9401988list
(22149) 2000 WD4910.248.19050.7750.37L47.841.0902000list
(32496) 2000 WX18210.248.01750.7751.63L523.340.9502000list
5120 Bitias10.247.98750.77n.a.L515.210.7801988list
12714 Alkimos10.147.81961.0454.62L428.48–1991list
7352 Hypsenor9.947.73155.67 47.07L56480.8501994list | 11 | 1 |
1870 Glaukos10.647.64942.23n.a.L55.99—1971list
4138 Kalchas10.146.46253.1661.04L429.20.8101973list
(23958) 1998 VD3010.246.00150.7747.91L45620.9901998list
4828 Misenus10.445.95446.30 43.22L512.870.9201988list
4057 Demophon10.145.68353.16n.a.L429.821.0601985list
4501 Eurypylos10.445.52446.30n.a.L46.05–1989list
4007 Euryalos10.345.51548.4853.89L46.39–1973list
5259 Epeigeus10.344.74142.5944.42L418.42–1989list
30705 Idaios10.444.54646.30n.a.L515.74–1977list
16560 Daitor10.743.86151.4243.38L5––1991list
(15977) 1998 MA1110.443.53046.3051.53L52500.9061998list
7543 Prylis10.642.89342.23n.a.L417.80–1973list
4827 Dares10.542.77044.22n.a.L519.00–1988list
1647 Menelaus10.542.71644.22n.a.L417.740.8661957list
(A) Used sources: WISE/NEOWISE catalog (NEOWISE_DIAM_V1 PDS, Grav, 2012); IRAS data (SIMPS v.6 catalog); and Akari catalog (Usui, 2011); RP: rotation period and V–I (color index) taken from the LCDB
Note: missing data was completed with figures from the JPL SBDB (query) and from the LCDB (query form) for the WISE/NEOWISE and SIMPS catalogs, respectively. These figures are given in italics. Also, listing is incomplete above #100.
References
1. "13366 (1998 US24)". Minor Planet Center. Retrieved 4 July 2018.
2. "JPL Small-Body Database Browser: 13366 (1998 US24)" (2018-05-21 last obs.). Jet Propulsion Laboratory. Retrieved 4 July 2018.
3. "List of Jupiter Trojans". Minor Planet Center. 1 July 2018. Retrieved 4 July 2018.
4. "Asteroid (13366) 1998 US24 – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 4 July 2018.
5. Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. arXiv:1209.1549. Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. S2CID 119101711. (online catalog)
6. Szabó, Gy. M.; Pál, A.; Kiss, Cs. ; Kiss, L. L.; Molnár, L.; Hanyecz, O.; et al. (March 2017). "The heart of the swarm: K2 photometry and rotational characteristics of 56 Jovian Trojan asteroids". Astronomy and Astrophysics. 599: 13. arXiv:1609.02760. Bibcode:2017A&A...599A..44S. doi:10.1051/0004-6361/201629401. S2CID 119275951.
7. "LCDB Data for (13366)". Asteroid Lightcurve Database (LCDB). Retrieved 4 July 2018.
8. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 4 July 2018.
9. Ryan, Erin Lee; Sharkey, Benjamin N. L.; Woodward, Charles E. (March 2017). "Trojan Asteroids in the Kepler Campaign 6 Field". The Astronomical Journal. 153 (3): 12. Bibcode:2017AJ....153..116R. doi:10.3847/1538-3881/153/3/116. S2CID 125570438.
External links
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Discovery Circumstances: Numbered Minor Planets (10001)-(15000) – Minor Planet Center
• Asteroid (13366) 1998 US24 at the Small Bodies Data Ferret
• (13366) 1998 US24 at AstDyS-2, Asteroids—Dynamic Site
• Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• (13366) 1998 US24 at the JPL Small-Body Database
Minor planets navigator
• 13365 Tenzinyama
• (13366) 1998 US24
• 13367 Jiří
Small Solar System bodies
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• Designation
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• MPC | 11 | 2 |
Pluto
Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Sun. It is the largest known trans-Neptunian object by volume, by a small margin, but is less massive than Eris. Like other Kuiper belt objects, Pluto is made primarily of ice and rock and is much smaller than the inner planets. Pluto has roughly one-sixth the mass of Earth's moon, and one-third its volume.
134340 Pluto
Pluto, imaged by the New Horizons spacecraft, July 2015. [lower-alpha 1] The most prominent feature in the image, the bright, youthful plains of Tombaugh Regio and Sputnik Planitia, can be seen at right. It contrasts the darker, cratered terrain of Belton Regio at lower left
Discovery
Discovered byClyde W. Tombaugh
Discovery siteLowell Observatory
Discovery dateFebruary 18, 1930
Designations
Designation
(134340) Pluto
Pronunciation/ˈpluːtoʊ/
Named after
Pluto
Minor planet category
• Dwarf planet
• Trans-Neptunian object
• Kuiper belt object
• Plutino
AdjectivesPlutonian /pluːˈtoʊniən/[1]
Symbol (historically astronomical, now mostly astrological) or (mostly astrological)
Orbital characteristics[2][lower-alpha 2]
Epoch J2000
Earliest precovery dateAugust 20, 1909
Aphelion
• 49.305 AU
• (7.37593 billion km)
• February 2114
Perihelion
• 29.658 AU
• (4.43682 billion km)[3]
• (September 5, 1989)[4]
Semi-major axis
• 39.482 AU
• (5.90638 billion km)
Eccentricity0.2488
Orbital period (sidereal)
• 247.94 years[3]
• 90,560 d[3]
Orbital period (synodic)
366.73 days[3]
Average orbital speed
4.743 km/s[3]
Mean anomaly
14.53 deg
Inclination
• 17.16°
• (11.88° to Sun's equator)
Longitude of ascending node
110.299°
Argument of perihelion
113.834°
Known satellites5
Physical characteristics
Dimensions2,376.6±1.6 km (observations consistent with a sphere, predicted deviations too small to be observed)[5]
Mean radius
• 1,188.3±0.8 km[6][5]
• 0.1868 Earths
Flattening<1%[7]
Surface area
• 1.774443×107 km2[lower-alpha 3]
• 0.035 Earths
Volume
• (7.057±0.004)×109 km3[lower-alpha 4]
• 0.00651 Earths
Mass
• (1.3025±0.0006)×1022 kg[8]
• 0.00218 Earths
• 0.177 Moons
Mean density
1.853±0.004 g/cm3[8]
Surface gravity
0.620 m/s2 (0.0632 g0)[lower-alpha 5]
Escape velocity
1.212 km/s[lower-alpha 6]
Synodic rotation period
• −6.38680 d
• −6 d, 9 h, 17 m, 00 s
[9]
Sidereal rotation period
• −6.387230 d
• −6 d, 9 h, 17 m, 36 s
Equatorial rotation velocity
47.18 km/h
Axial tilt
122.53° (to orbit)[3]
North pole right ascension
132.993°[10]
North pole declination
−6.163°[10]
Albedo0.52 geometric[3]
0.72 Bond[3]
Surface temp. min mean max
Kelvin 33 K 44 K (−229 °C) 55 K
Apparent magnitude
13.65[3] to 16.3[11]
(mean is 15.1)[3]
Absolute magnitude (H)
−0.44[12]
Angular diameter
0.06″ to 0.11″[3][lower-alpha 7]
Atmosphere
Surface pressure
1.0 Pa (2015)[7][13]
Composition by volumeNitrogen, methane, carbon monoxide[14]
Pluto has a moderately eccentric and inclined orbit, ranging from 30 to 49 astronomical units (4.5 to 7.3 billion kilometers; 2.8 to 4.6 billion miles) from the Sun. Light from the Sun takes 5.5 hours to reach Pluto at its orbital distance of 39.5 AU (5.91 billion km; 3.67 billion mi). Pluto's eccentric orbit periodically brings it closer to the Sun than Neptune, but a stable orbital resonance prevents them from colliding.
Pluto has five known moons: Charon, the largest, whose diameter is just over half that of Pluto; Styx; Nix; Kerberos; and Hydra. Pluto and Charon are sometimes considered a binary system because the barycenter of their orbits does not lie within either body, and they are tidally locked. The New Horizons mission was the first spacecraft to visit Pluto and its moons, making a flyby on July 14, 2015, and taking detailed measurements and observations.
Pluto was discovered in 1930 by Clyde W. Tombaugh, making it by far the first known object in the Kuiper belt. It was immediately hailed as the ninth planet, but it was always the odd object out,[15]: 27 and its planetary status was questioned when it was found to be much smaller than expected. These doubts increased following the discovery of additional objects in the Kuiper belt starting in the 1990s, and particularly the more massive scattered disk object Eris in 2005. In 2006, the International Astronomical Union (IAU) formally redefined the term planet to exclude dwarf planets such as Pluto. Many planetary astronomers, however, continue to consider Pluto and other dwarf planets to be planets.
History
Discovery
Further information: Planets beyond Neptune
In the 1840s, Urbain Le Verrier used Newtonian mechanics to predict the position of the then-undiscovered planet Neptune after analyzing perturbations in the orbit of Uranus. Subsequent observations of Neptune in the late 19th century led astronomers to speculate that Uranus's orbit was being disturbed by another planet besides Neptune. [16]
In 1906, Percival Lowell—a wealthy Bostonian who had founded Lowell Observatory in Flagstaff, Arizona, in 1894—started an extensive project in search of a possible ninth planet, which he termed "Planet X". [17] By 1909, Lowell and William H. Pickering had suggested several possible celestial coordinates for such a planet. [18] Lowell and his observatory conducted his search, using mathematical calculations made by Elizabeth Williams, until his death in 1916, but to no avail. Unknown to Lowell, his surveys had captured two faint images of Pluto on March 19 and April 7, 1915, but they were not recognized for what they were. [18][19] There are fourteen other known precovery observations, with the earliest made by the Yerkes Observatory on August 20, 1909. [20]
Percival's widow, Constance Lowell, entered into a ten-year legal battle with the Lowell Observatory over her husband's legacy, and the search for Planet X did not resume until 1929. [21] Vesto Melvin Slipher, the observatory director, gave the job of locating Planet X to 23-year-old Clyde Tombaugh, who had just arrived at the observatory after Slipher had been impressed by a sample of his astronomical drawings. [21]
Tombaugh's task was to systematically image the night sky in pairs of photographs, then examine each pair and determine whether any objects had shifted position. Using a blink comparator, he rapidly shifted back and forth between views of each of the plates to create the illusion of movement of any objects that had changed position or appearance between photographs. On February 18, 1930, after nearly a year of searching, Tombaugh discovered a possible moving object on photographic plates taken on January 23 and 29. A lesser-quality photograph taken on January 21 helped confirm the movement. [22] After the observatory obtained further confirmatory photographs, news of the discovery was telegraphed to the Harvard College Observatory on March 13, 1930. [18] | 12 | 0 |
One Plutonian year corresponds to 247.94 Earth years;[3] thus, in 2178, Pluto will complete its first orbit since its discovery.
Name and symbol
The name Pluto came from the Roman god of the underworld; and it is also an epithet for Hades (the Greek equivalent of Pluto).
Upon the announcement of the discovery, Lowell Observatory received over a thousand suggestions for names. [23] Three names topped the list: Minerva, Pluto and Cronus. 'Minerva' was the Lowell staff's first choice[24] but was rejected because it had already been used for an asteroid; Cronus was disfavored because it was promoted by an unpopular and egocentric astronomer, Thomas Jefferson Jackson See. A vote was then taken and 'Pluto' was the unanimous choice. To make sure the name stuck, and that the planet would not suffer changes in its name as Uranus had, Lowell Observatory proposed the name to the American Astronomical Society and the Royal Astronomical Society; both approved it unanimously. [15]: 136 [25] The name was published on May 1, 1930. [26][27]
The name Pluto had received some 150 nominations among the letters and telegrams sent to Lowell. The first[lower-alpha 8] had been from Venetia Burney (1918–2009), an eleven-year-old schoolgirl in Oxford, England, who was interested in classical mythology. [15][26] She had suggested it to her grandfather Falconer Madan when he read the news of Pluto's discovery to his family over breakfast; Madan passed the suggestion to astronomy professor Herbert Hall Turner, who cabled it to colleagues at Lowell on March 16, three days after the announcement. [24][26]
The name 'Pluto' was mythologically appropriate: the god Pluto was one of six surviving children of Saturn, and the others had already all been chosen as names of major or minor planets (his brothers Jupiter and Neptune, and his sisters Ceres, Juno and Vesta). Both the god and the planet inhabited "gloomy" regions, and the god was able to make himself invisible, as the planet had been for so long. [29] The choice was further helped by the fact that the first two letters of Pluto were the initials of Percival Lowell; indeed, 'Percival' had been one of the more popular suggestions for a name for the new planet. [24][30] Pluto's planetary symbol ⟨⟩ was then created as a monogram of the letters "PL". [31] This symbol is rarely used in astronomy anymore,[lower-alpha 9] though it is still common in astrology. However, the most common astrological symbol for Pluto, occasionally used in astronomy as well, is an orb (possibly representing Pluto's invisibility cap) over Pluto's bident ⟨⟩, which dates to the early 1930s. [35][lower-alpha 10]
The name 'Pluto' was soon embraced by wider culture. In 1930, Walt Disney was apparently inspired by it when he introduced for Mickey Mouse a canine companion named Pluto, although Disney animator Ben Sharpsteen could not confirm why the name was given. [39] In 1941, Glenn T. Seaborg named the newly created element plutonium after Pluto, in keeping with the tradition of naming elements after newly discovered planets, following uranium, which was named after Uranus, and neptunium, which was named after Neptune. [40]
Most languages use the name "Pluto" in various transliterations. [lower-alpha 11] In Japanese, Houei Nojiri suggested the calque Meiōsei (冥王星, "Star of the King (God) of the Underworld"), and this was borrowed into Chinese and Korean. Some languages of India use the name Pluto, but others, such as Hindi, use the name of Yama, the God of Death in Hinduism. [41] Polynesian languages also tend to use the indigenous god of the underworld, as in Māori Whiro. [41] Vietnamese might be expected to follow Chinese, but does not because the Sino-Vietnamese word 冥 minh "dark" is homophonous with 明 minh "bright". Vietnamese instead uses Yama, which is also a Buddhist deity, in the form of Sao Diêm Vương 星閻王 "Yama's Star", derived from Chinese 閻王 Yán Wáng / Yìhm Wòhng "King Yama". [41][42][43]
Planet X disproved
Once Pluto was found, its faintness and lack of a viewable disc cast doubt on the idea that it was Lowell's Planet X. [17] Estimates of Pluto's mass were revised downward throughout the 20th century. [44]
Mass estimates for Pluto
Year Mass Estimate by
1915
7 Earths
Lowell (prediction for Planet X)[17]
1931
1 Earth
Nicholson & Mayall[45][46][47]
1948
0.1 (1/10) Earth
Kuiper[48]
1976
0.01 (1/100) Earth
Cruikshank, Pilcher, & Morrison[49]
1978
0.0015 (1/650) Earth
Christy & Harrington[50]
2006
0.00218 (1/459) Earth
Buie et al. [51]
Astronomers initially calculated its mass based on its presumed effect on Neptune and Uranus. In 1931, Pluto was calculated to be roughly the mass of Earth, with further calculations in 1948 bringing the mass down to roughly that of Mars. [46][48] In 1976, Dale Cruikshank, Carl Pilcher and David Morrison of the University of Hawaiʻi calculated Pluto's albedo for the first time, finding that it matched that for methane ice; this meant Pluto had to be exceptionally luminous for its size and therefore could not be more than 1 percent the mass of Earth. [49] (Pluto's albedo is 1.4–1.9 times that of Earth. [3])
In 1978, the discovery of Pluto's moon Charon allowed the measurement of Pluto's mass for the first time: roughly 0.2% that of Earth, and far too small to account for the discrepancies in the orbit of Uranus. Subsequent searches for an alternative Planet X, notably by Robert Sutton Harrington,[52] failed. In 1992, Myles Standish used data from Voyager 2's flyby of Neptune in 1989, which had revised the estimates of Neptune's mass downward by 0.5%—an amount comparable to the mass of Mars—to recalculate its gravitational effect on Uranus. With the new figures added in, the discrepancies, and with them the need for a Planet X, vanished. [53] As of 2000 the majority of scientists agree that Planet X, as Lowell defined it, does not exist. [54] Lowell had made a prediction of Planet X's orbit and position in 1915 that was fairly close to Pluto's actual orbit and its position at that time; Ernest W. Brown concluded soon after Pluto's discovery that this was a coincidence. [55]
Classification
Further information: Definition of planet
From 1992 onward, many bodies were discovered orbiting in the same volume as Pluto, showing that Pluto is part of a population of objects called the Kuiper belt. This made its official status as a planet controversial, with many questioning whether Pluto should be considered together with or separately from its surrounding population. Museum and planetarium directors occasionally created controversy by omitting Pluto from planetary models of the Solar System. In February 2000 the Hayden Planetarium in New York City displayed a Solar System model of only eight planets, which made headlines almost a year later. [56]
Ceres, Pallas, Juno and Vesta lost their planet status among most astronomers after the discovery of many other asteroids. On the other hand, planetary geologists often regarded Ceres, and less often Pallas and Vesta, as being different from smaller asteroids because they were large enough to have undergone geological evolution. [57] Although the first Kuiper belt objects discovered were quite small, objects increasingly closer in size to Pluto were soon discovered, some large enough (like Pluto itself) to satisfy geological but not dynamical ideas of planethood. [58] On July 29, 2005, the debate became unavoidable, astronomers at Caltech announced the discovery of a new trans-Neptunian object, Eris, which was substantially more massive than Pluto and the most massive object discovered in the Solar System since Triton in 1846. Its discoverers and the press initially called it the tenth planet, although there was no official consensus at the time on whether to call it a planet. [59] Others in the astronomical community considered the discovery the strongest argument for reclassifying Pluto as a minor planet. [60]
IAU classification
Main article: IAU definition of planet
The debate came to a head in August 2006, with an IAU resolution that created an official definition for the term "planet". According to this resolution, there are three conditions for an object in the Solar System to be considered a planet:
• The object must be in orbit around the Sun.
• The object must be massive enough to be rounded by its own gravity. More specifically, its own gravity should pull it into a shape defined by hydrostatic equilibrium.
• It must have cleared the neighborhood around its orbit. [61][62] | 12 | 1 |
Pluto fails to meet the third condition. [63] Its mass is substantially less than the combined mass of the other objects in its orbit: 0.07 times, in contrast to Earth, which is 1.7 million times the remaining mass in its orbit (excluding the moon). [64][62] The IAU further decided that bodies that, like Pluto, meet criteria 1 and 2, but do not meet criterion 3 would be called dwarf planets. In September 2006, the IAU included Pluto, and Eris and its moon Dysnomia, in their Minor Planet Catalogue, giving them the official minor-planet designations "(134340) Pluto", "(136199) Eris", and "(136199) Eris I Dysnomia". [65] Had Pluto been included upon its discovery in 1930, it would have likely been designated 1164, following 1163 Saga, which was discovered a month earlier. [66]
There has been some resistance within the astronomical community toward the reclassification, and in particular planetary scientists often continue to reject it, considering Pluto, Charon, and Eris to be planets for the same reason they do so for Ceres. In effect, this amounts to accepting only the second clause of the IAU definition. [67][68][69] Alan Stern, principal investigator with NASA's New Horizons mission to Pluto, derided the IAU resolution. [70][71] He also stated that because less than five percent of astronomers voted for it, the decision was not representative of the entire astronomical community. [71] Marc W. Buie, then at the Lowell Observatory, petitioned against the definition. [72] Others have supported the IAU, for example Mike Brown, the astronomer who discovered Eris. [73]
Public reception to the IAU decision was mixed. A resolution introduced in the California State Assembly facetiously called the IAU decision a "scientific heresy". [74] The New Mexico House of Representatives passed a resolution in honor of Clyde Tombaugh, the discoverer of Pluto and a longtime resident of that state, that declared that Pluto will always be considered a planet while in New Mexican skies and that March 13, 2007 was Pluto Planet Day. [75][76] The Illinois Senate passed a similar resolution in 2009 on the basis that Tombaugh was born in Illinois. The resolution asserted that Pluto was "unfairly downgraded to a 'dwarf' planet" by the IAU. "[77] Some members of the public have also rejected the change, citing the disagreement within the scientific community on the issue, or for sentimental reasons, maintaining that they have always known Pluto as a planet and will continue to do so regardless of the IAU decision. [78] In 2006, in its 17th annual words-of-the-year vote, the American Dialect Society voted plutoed as the word of the year. To "pluto" is to "demote or devalue someone or something". [79]
Researchers on both sides of the debate gathered in August 2008, at the Johns Hopkins University Applied Physics Laboratory for a conference that included back-to-back talks on the IAU definition of a planet. [80] Entitled "The Great Planet Debate",[81] the conference published a post-conference press release indicating that scientists could not come to a consensus about the definition of planet. [82] In June 2008, the IAU had announced in a press release that the term "plutoid" would henceforth be used to refer to Pluto and other planetary-mass objects that have an orbital semi-major axis greater than that of Neptune, though the term has not seen significant use. [83][84][85]
In April 2024, Arizona (where Pluto was first discovered in 1930) passed a law naming Pluto as the official state planet. [86]
Orbit
Pluto's orbital period is about 248 years. Its orbital characteristics are substantially different from those of the planets, which follow nearly circular orbits around the Sun close to a flat reference plane called the ecliptic. In contrast, Pluto's orbit is moderately inclined relative to the ecliptic (over 17°) and moderately eccentric (elliptical). This eccentricity means a small region of Pluto's orbit lies closer to the Sun than Neptune's. The Pluto–Charon barycenter came to perihelion on September 5, 1989,[4][lower-alpha 12] and was last closer to the Sun than Neptune between February 7, 1979, and February 11, 1999. [87]
Although the 3:2 resonance with Neptune (see below) is maintained, Pluto's inclination and eccentricity behave in a chaotic manner. Computer simulations can be used to predict its position for several million years (both forward and backward in time), but after intervals much longer than the Lyapunov time of 10–20 million years, calculations become unreliable: Pluto is sensitive to immeasurably small details of the Solar System, hard-to-predict factors that will gradually change Pluto's position in its orbit. [88][89]
The semi-major axis of Pluto's orbit varies between about 39.3 and 39.6 AU with a period of about 19,951 years, corresponding to an orbital period varying between 246 and 249 years. The semi-major axis and period are presently getting longer. [90]
Relationship with Neptune
Despite Pluto's orbit appearing to cross that of Neptune when viewed from north or south of the Solar System, the two objects' orbits do not intersect. When Pluto is closest to the Sun, and close to Neptune's orbit as viewed from such a position, it is also the farthest north of Neptune's path. Pluto's orbit passes about 8 AU north of that of Neptune, preventing a collision. [91][92][93][lower-alpha 13]
This alone is not enough to protect Pluto; perturbations from the planets (especially Neptune) could alter Pluto's orbit (such as its orbital precession) over millions of years so that a collision could happen. However, Pluto is also protected by its 2:3 orbital resonance with Neptune: for every two orbits that Pluto makes around the Sun, Neptune makes three, in a frame of reference that rotates at the rate that Pluto's perihelion precesses (about 0.97×10−4 degrees per year[90]). Each cycle lasts about 495 years. (There are many other objects in this same resonance, called plutinos.) At present, in each 495-year cycle, the first time Pluto is at perihelion (such as in 1989), Neptune is 57° ahead of Pluto. By Pluto's second passage through perihelion, Neptune will have completed a further one and a half of its own orbits, and will be 123° behind Pluto. [95] Pluto and Neptune's minimum separation is over 17 AU, which is greater than Pluto's minimum separation from Uranus (11 AU). [93] The minimum separation between Pluto and Neptune actually occurs near the time of Pluto's aphelion. [90]
The 2:3 resonance between the two bodies is highly stable and has been preserved over millions of years. [96] This prevents their orbits from changing relative to one another, so the two bodies can never pass near each other. Even if Pluto's orbit were not inclined, the two bodies could never collide. [93] When Pluto's period is slightly different from 3/2 of Neptune's, the pattern of its distance from Neptune will drift. Near perihelion Pluto moves interior to Neptune's orbit and is therefore moving faster, so during the first of two orbits in the 495-year cycle, it is approaching Neptune from behind. At present it remains between 50° and 65° behind Neptune for 100 years (e.g. 1937–2036). [95] The gravitational pull between the two causes angular momentum to be transferred to Pluto. This situation moves Pluto into a slightly larger orbit, where it has a slightly longer period, according to Kepler's third law. After several such repetitions, Pluto is sufficiently delayed that at the second perihelion of each cycle it will not be far ahead of Neptune coming behind it, and Neptune will start to decrease Pluto's period again. The whole cycle takes about 20,000 years to complete. [93][96][97]
Other factors
Numerical studies have shown that over millions of years, the general nature of the alignment between the orbits of Pluto and Neptune does not change. [91][90] There are several other resonances and interactions that enhance Pluto's stability. These arise principally from two additional mechanisms (besides the 2:3 mean-motion resonance).
First, Pluto's argument of perihelion, the angle between the point where it crosses the ecliptic (or the invariant plane) and the point where it is closest to the Sun, librates around 90°. [90] This means that when Pluto is closest to the Sun, it is at its farthest north of the plane of the Solar System, preventing encounters with Neptune. This is a consequence of the Kozai mechanism,[91] which relates the eccentricity of an orbit to its inclination to a larger perturbing body—in this case, Neptune. Relative to Neptune, the amplitude of libration is 38°, and so the angular separation of Pluto's perihelion to the orbit of Neptune is always greater than 52° (90°–38°). The closest such angular separation occurs every 10,000 years. [96] | 12 | 2 |
Second, the longitudes of ascending nodes of the two bodies—the points where they cross the invariant plane—are in near-resonance with the above libration. When the two longitudes are the same—that is, when one could draw a straight line through both nodes and the Sun—Pluto's perihelion lies exactly at 90°, and hence it comes closest to the Sun when it is furthest north of Neptune's orbit. This is known as the 1:1 superresonance. All the Jovian planets (Jupiter, Saturn, Uranus, and Neptune) play a role in the creation of the superresonance. [91]
Orcus
The 2nd-largest known plutino, Orcus, has a diameter around 900 km and is in a very similar orbit to that of Pluto. However, the orbits of Pluto and Orcus are out of phase, so that the two never approach each other. It has been termed the "anti-Pluto", and is named for the Etruscan counterpart to the god Pluto.
Rotation
Pluto's rotation period, its day, is equal to 6.387 Earth days. [3][98] Like Uranus and 2 Pallas, Pluto rotates on its "side" in its orbital plane, with an axial tilt of 120°, and so its seasonal variation is extreme; at its solstices, one-fourth of its surface is in continuous daylight, whereas another fourth is in continuous darkness. [99] The reason for this unusual orientation has been debated. Research from the University of Arizona has suggested that it may be due to the way that a body's spin will always adjust to minimise energy. This could mean a body reorienting itself to put extraneous mass near the equator and regions lacking mass tend towards the poles. This is called polar wander. [100] According to a paper released from the University of Arizona, this could be caused by masses of frozen nitrogen building up in shadowed areas of the dwarf planet. These masses would cause the body to reorient itself, leading to its unusual axial tilt of 120°. The buildup of nitrogen is due to Pluto's vast distance from the Sun. At the equator, temperatures can drop to −240 °C (−400.0 °F; 33.1 K), causing nitrogen to freeze as water would freeze on Earth. The same polar wandering effect seen on Pluto would be observed on Earth were the Antarctic ice sheet several times larger. [101]
Geology
Main articles: Geology of Pluto and Geography of Pluto
Surface
The plains on Pluto's surface are composed of more than 98 percent nitrogen ice, with traces of methane and carbon monoxide. [102] Nitrogen and carbon monoxide are most abundant on the anti-Charon face of Pluto (around 180° longitude, where Tombaugh Regio's western lobe, Sputnik Planitia, is located), whereas methane is most abundant near 300° east. [103] The mountains are made of water ice. [104] Pluto's surface is quite varied, with large differences in both brightness and color. [105] Pluto is one of the most contrastive bodies in the Solar System, with as much contrast as Saturn's moon Iapetus. [106] The color varies from charcoal black, to dark orange and white. [107] Pluto's color is more similar to that of Io with slightly more orange and significantly less red than Mars. [108] Notable geographical features include Tombaugh Regio, or the "Heart" (a large bright area on the side opposite Charon), Belton Regio,[6] or the "Whale" (a large dark area on the trailing hemisphere), and the "Brass Knuckles" (a series of equatorial dark areas on the leading hemisphere).
Sputnik Planitia, the western lobe of the "Heart", is a 1,000 km-wide basin of frozen nitrogen and carbon monoxide ices, divided into polygonal cells, which are interpreted as convection cells that carry floating blocks of water ice crust and sublimation pits towards their margins;[109][110][111] there are obvious signs of glacial flows both into and out of the basin. [112][113] It has no craters that were visible to New Horizons, indicating that its surface is less than 10 million years old. [114] Latest studies have shown that the surface has an age of 180000+90000
−40000 years. [115] The New Horizons science team summarized initial findings as "Pluto displays a surprisingly wide variety of geological landforms, including those resulting from glaciological and surface–atmosphere interactions as well as impact, tectonic, possible cryovolcanic, and mass-wasting processes. "[7]
In Western parts of Sputnik Planitia there are fields of transverse dunes formed by the winds blowing from the center of Sputnik Planitia in the direction of surrounding mountains. The dune wavelengths are in the range of 0.4–1 km and likely consist of methane particles 200–300 μm in size. [116]
• Multispectral Visual Imaging Camera image of Pluto in enhanced color to bring out differences in surface composition.
• Distribution of numerous impact craters and basins on both Pluto and Charon. The variation in density (with none found in Sputnik Planitia) indicates a long history of varying geological activity. Precisely for this reason, the confidence of numerous craters on Pluto remain uncertain. [117] The lack of craters on the left and right of each map is due to low-resolution coverage of those anti-encounter regions.
• Geologic map of Sputnik Planitia and surroundings (context), with convection cell margins outlined in black
• Regions where water ice has been detected (blue regions)
Internal structure
"Life on Pluto" redirects here. For fiction about aliens from Pluto, see Life on Pluto in fiction.
Pluto's density is 1.853±0.004 g/cm3. [8] Because the decay of radioactive elements would eventually heat the ices enough for the rock to separate from them, scientists expect that Pluto's internal structure is differentiated, with the rocky material having settled into a dense core surrounded by a mantle of water ice. The pre–New Horizons estimate for the diameter of the core is 1700 km, 70% of Pluto's diameter. [118] It is possible that such heating continues, creating a subsurface ocean of liquid water 100 to 180 km thick at the core–mantle boundary. [118][119][120] In September 2016, scientists at Brown University simulated the impact thought to have formed Sputnik Planitia, and showed that it might have been the result of liquid water upwelling from below after the collision, implying the existence of a subsurface ocean at least 100 km deep. [121] In June 2020, astronomers reported evidence that Pluto may have had a subsurface ocean, and consequently may have been habitable, when it was first formed. [122][123] In March 2022, a team of researchers proposed that the mountains Wright Mons and Piccard Mons are actually a merger of many smaller cryovolcanic domes, suggesting a source of heat on the body at levels previously thought not possible. [124]
Mass and size
Pluto's diameter is 2376.6±3.2 km[5] and its mass is (1.303±0.003)×1022 kg, 17.7% that of the Moon (0.22% that of Earth). [125] Its surface area is 1.774443×107 km2, or just slightly bigger than Russia or Antarctica (particularly including the Antarctic sea ice during winter). Its surface gravity is 0.063 g (compared to 1 g for Earth and 0.17 g for the Moon). [3] This gives Pluto an escape velocity of 4,363.2 km per hour / 2,711.167 miles per hour (as compared to Earth's 40,270 km per hour / 25,020 miles per hour). Pluto is more than twice the diameter and a dozen times the mass of Ceres, the largest object in the asteroid belt. It is less massive than the dwarf planet Eris, a trans-Neptunian object discovered in 2005, though Pluto has a larger diameter of 2,376.6 km[5] compared to Eris's approximate diameter of 2,326 km. [126]
With less than 0.2 lunar masses, Pluto is much less massive than the terrestrial planets, and also less massive than seven moons: Ganymede, Titan, Callisto, Io, the Moon, Europa, and Triton. The mass is much less than thought before Charon was discovered. [127]
The discovery of Pluto's satellite Charon in 1978 enabled a determination of the mass of the Pluto–Charon system by application of Newton's formulation of Kepler's third law. Observations of Pluto in occultation with Charon allowed scientists to establish Pluto's diameter more accurately, whereas the invention of adaptive optics allowed them to determine its shape more accurately. [128]
Determinations of Pluto's size have been complicated by its atmosphere[129] and hydrocarbon haze. [130] In March 2014, Lellouch, de Bergh et al. | 12 | 3 |
published findings regarding methane mixing ratios in Pluto's atmosphere consistent with a Plutonian diameter greater than 2,360 km, with a "best guess" of 2,368 km. [131] On July 13, 2015, images from NASA's New Horizons mission Long Range Reconnaissance Imager (LORRI), along with data from the other instruments, determined Pluto's diameter to be 2,370 km (1,473 mi),[126][132] which was later revised to be 2,372 km (1,474 mi) on July 24,[133] and later to 2374±8 km. [7] Using radio occultation data from the New Horizons Radio Science Experiment (REX), the diameter was found to be 2376.6±3.2 km. [5]
The masses of Pluto and Charon compared to other dwarf planets (Eris, Haumea, Makemake, Gonggong, Quaoar, Orcus, Ceres) and to the icy moons Triton (Neptune I), Titania (Uranus III), Oberon (Uranus IV), Rhea (Saturn V) and Iapetus (Saturn VIII). The unit of mass is ×1021 kg.
Atmosphere
Main article: Atmosphere of Pluto
Pluto has a tenuous atmosphere consisting of nitrogen (N2), methane (CH4), and carbon monoxide (CO), which are in equilibrium with their ices on Pluto's surface. [134][135] According to the measurements by New Horizons, the surface pressure is about 1 Pa (10 μbar),[7] roughly one million to 100,000 times less than Earth's atmospheric pressure. It was initially thought that, as Pluto moves away from the Sun, its atmosphere should gradually freeze onto the surface; studies of New Horizons data and ground-based occultations show that Pluto's atmospheric density increases, and that it likely remains gaseous throughout Pluto's orbit. [136][137] New Horizons observations showed that atmospheric escape of nitrogen to be 10,000 times less than expected. [137] Alan Stern has contended that even a small increase in Pluto's surface temperature can lead to exponential increases in Pluto's atmospheric density; from 18 hPa to as much as 280 hPa (three times that of Mars to a quarter that of the Earth). At such densities, nitrogen could flow across the surface as liquid. [137] Just like sweat cools the body as it evaporates from the skin, the sublimation of Pluto's atmosphere cools its surface. [138] Pluto has no or almost no troposphere; observations by New Horizons suggest only a thin tropospheric boundary layer. Its thickness in the place of measurement was 4 km, and the temperature was 37±3 K. The layer is not continuous. [139]
In July 2019, an occultation by Pluto showed that its atmospheric pressure, against expectations, had fallen by 20% since 2016. [140] In 2021, astronomers at the Southwest Research Institute confirmed the result using data from an occultation in 2018, which showed that light was appearing less gradually from behind Pluto's disc, indicating a thinning atmosphere. [141]
The presence of methane, a powerful greenhouse gas, in Pluto's atmosphere creates a temperature inversion, with the average temperature of its atmosphere tens of degrees warmer than its surface,[142] though observations by New Horizons have revealed Pluto's upper atmosphere to be far colder than expected (70 K, as opposed to about 100 K). [137] Pluto's atmosphere is divided into roughly 20 regularly spaced haze layers up to 150 km high,[7] thought to be the result of pressure waves created by airflow across Pluto's mountains. [137]
Natural satellites
Main article: Moons of Pluto
Pluto has five known natural satellites. The largest and closest to Pluto is Charon. First identified in 1978 by astronomer James Christy, Charon is the only moon of Pluto that may be in hydrostatic equilibrium. Charon's mass is sufficient to cause the barycenter of the Pluto–Charon system to be outside Pluto. Beyond Charon there are four much smaller circumbinary moons. In order of distance from Pluto they are Styx, Nix, Kerberos, and Hydra. Nix and Hydra were both discovered in 2005,[143] Kerberos was discovered in 2011,[144] and Styx was discovered in 2012. [145] The satellites' orbits are circular (eccentricity < 0.006) and coplanar with Pluto's equator (inclination < 1°),[146][147] and therefore tilted approximately 120° relative to Pluto's orbit. The Plutonian system is highly compact: the five known satellites orbit within the inner 3% of the region where prograde orbits would be stable. [148]
The orbital periods of all Pluto's moons are linked in a system of orbital resonances and near-resonances. [147][149] When precession is accounted for, the orbital periods of Styx, Nix, and Hydra are in an exact 18:22:33 ratio. [147] There is a sequence of approximate ratios, 3:4:5:6, between the periods of Styx, Nix, Kerberos, and Hydra with that of Charon; the ratios become closer to being exact the further out the moons are. [147][150]
The Pluto–Charon system is one of the few in the Solar System whose barycenter lies outside the primary body; the Patroclus–Menoetius system is a smaller example, and the Sun–Jupiter system is the only larger one. [151] The similarity in size of Charon and Pluto has prompted some astronomers to call it a double dwarf planet. [152] The system is also unusual among planetary systems in that each is tidally locked to the other, which means that Pluto and Charon always have the same hemisphere facing each other — a property shared by only one other known system, Eris and Dysnomia. [153] From any position on either body, the other is always at the same position in the sky, or always obscured. [154] This also means that the rotation period of each is equal to the time it takes the entire system to rotate around its barycenter. [98]
Pluto's moons are hypothesized to have been formed by a collision between Pluto and a similar-sized body, early in the history of the Solar System. The collision released material that consolidated into the moons around Pluto. [155]
Quasi-satellite
In 2012, it was calculated that 15810 Arawn could be a quasi-satellite of Pluto, a specific type of co-orbital configuration. [156] According to the calculations, the object would be a quasi-satellite of Pluto for about 350,000 years out of every two-million-year period. [156][157] Measurements made by the New Horizons spacecraft in 2015 made it possible to calculate the orbit of Arawn more accurately,[158] and confirmed the earlier ones. [159] However, it is not agreed upon among astronomers whether Arawn should be classified as a quasi-satellite of Pluto based on its orbital dynamics, since its orbit is primarily controlled by Neptune with only occasional perturbations by Pluto. [160][158][159]
Origin
Further information: Kuiper belt and Nice model
Pluto's origin and identity had long puzzled astronomers. One early hypothesis was that Pluto was an escaped moon of Neptune[161] knocked out of orbit by Neptune's largest moon, Triton. This idea was eventually rejected after dynamical studies showed it to be impossible because Pluto never approaches Neptune in its orbit. [162]
Pluto's true place in the Solar System began to reveal itself only in 1992, when astronomers began to find small icy objects beyond Neptune that were similar to Pluto not only in orbit but also in size and composition. This trans-Neptunian population is thought to be the source of many short-period comets. Pluto is the largest member of the Kuiper belt,[lower-alpha 14] a stable belt of objects located between 30 and 50 AU from the Sun. As of 2011, surveys of the Kuiper belt to magnitude 21 were nearly complete and any remaining Pluto-sized objects are expected to be beyond 100 AU from the Sun. [163] Like other Kuiper-belt objects (KBOs), Pluto shares features with comets; for example, the solar wind is gradually blowing Pluto's surface into space. [164] It has been claimed that if Pluto were placed as near to the Sun as Earth, it would develop a tail, as comets do. [165] This claim has been disputed with the argument that Pluto's escape velocity is too high for this to happen. [166] It has been proposed that Pluto may have formed as a result of the agglomeration of numerous comets and Kuiper-belt objects. [167][168]
Though Pluto is the largest Kuiper belt object discovered,[130] Neptune's moon Triton, which is larger than Pluto, is similar to it both geologically and atmospherically, and is thought to be a captured Kuiper belt object. [169] Eris (see above) is about the same size as Pluto (though more massive) but is not strictly considered a member of the Kuiper belt population. Rather, it is considered a member of a linked population called the scattered disc. [170] | 12 | 4 |
Like other members of the Kuiper belt, Pluto is thought to be a residual planetesimal; a component of the original protoplanetary disc around the Sun that failed to fully coalesce into a full-fledged planet. Most astronomers agree that Pluto owes its position to a sudden migration undergone by Neptune early in the Solar System's formation. As Neptune migrated outward, it approached the objects in the proto-Kuiper belt, setting one in orbit around itself (Triton), locking others into resonances, and knocking others into chaotic orbits. The objects in the scattered disc, a dynamically unstable region overlapping the Kuiper belt, are thought to have been placed in their positions by interactions with Neptune's migrating resonances. [171] A computer model created in 2004 by Alessandro Morbidelli of the Observatoire de la Côte d'Azur in Nice suggested that the migration of Neptune into the Kuiper belt may have been triggered by the formation of a 1:2 resonance between Jupiter and Saturn, which created a gravitational push that propelled both Uranus and Neptune into higher orbits and caused them to switch places, ultimately doubling Neptune's distance from the Sun. The resultant expulsion of objects from the proto-Kuiper belt could also explain the Late Heavy Bombardment 600 million years after the Solar System's formation and the origin of the Jupiter trojans. [172] It is possible that Pluto had a near-circular orbit about 33 AU from the Sun before Neptune's migration perturbed it into a resonant capture. [173] The Nice model requires that there were about a thousand Pluto-sized bodies in the original planetesimal disk, which included Triton and Eris. [172]
Observation and exploration
Observation
Pluto's distance from Earth makes its in-depth study and exploration difficult. Pluto's visual apparent magnitude averages 15.1, brightening to 13.65 at perihelion. [3] To see it, a telescope is required; around 30 cm (12 in) aperture being desirable. [174] It looks star-like and without a visible disk even in large telescopes,[175] because its angular diameter is maximum 0.11". [3]
The earliest maps of Pluto, made in the late 1980s, were brightness maps created from close observations of eclipses by its largest moon, Charon. Observations were made of the change in the total average brightness of the Pluto–Charon system during the eclipses. For example, eclipsing a bright spot on Pluto makes a bigger total brightness change than eclipsing a dark spot. Computer processing of many such observations can be used to create a brightness map. This method can also track changes in brightness over time. [176][177]
Better maps were produced from images taken by the Hubble Space Telescope (HST), which offered higher resolution, and showed considerably more detail,[106] resolving variations several hundred kilometers across, including polar regions and large bright spots. [108] These maps were produced by complex computer processing, which finds the best-fit projected maps for the few pixels of the Hubble images. [178] These remained the most detailed maps of Pluto until the flyby of New Horizons in July 2015, because the two cameras on the HST used for these maps were no longer in service. [178]
Exploration
Main articles: Exploration of Pluto and New Horizons
The New Horizons spacecraft, which flew by Pluto in July 2015, is the first and so far only attempt to explore Pluto directly. Launched in 2006, it captured its first (distant) images of Pluto in late September 2006 during a test of the Long Range Reconnaissance Imager. [179] The images, taken from a distance of approximately 4.2 billion kilometers, confirmed the spacecraft's ability to track distant targets, critical for maneuvering toward Pluto and other Kuiper belt objects. In early 2007 the craft made use of a gravity assist from Jupiter.
New Horizons made its closest approach to Pluto on July 14, 2015, after a 3,462-day journey across the Solar System. Scientific observations of Pluto began five months before the closest approach and continued for at least a month after the encounter. Observations were conducted using a remote sensing package that included imaging instruments and a radio science investigation tool, as well as spectroscopic and other experiments. The scientific goals of New Horizons were to characterize the global geology and morphology of Pluto and its moon Charon, map their surface composition, and analyze Pluto's neutral atmosphere and its escape rate. On October 25, 2016, at 05:48 pm ET, the last bit of data (of a total of 50 billion bits of data; or 6.25 gigabytes) was received from New Horizons from its close encounter with Pluto. [180][181][182][183]
Since the New Horizons flyby, scientists have advocated for an orbiter mission that would return to Pluto to fulfill new science objectives. [184][185][186] They include mapping the surface at 9.1 m (30 ft) per pixel, observations of Pluto's smaller satellites, observations of how Pluto changes as it rotates on its axis, investigations of a possible subsurface ocean, and topographic mapping of Pluto's regions that are covered in long-term darkness due to its axial tilt. The last objective could be accomplished using laser pulses to generate a complete topographic map of Pluto. New Horizons principal investigator Alan Stern has advocated for a Cassini-style orbiter that would launch around 2030 (the 100th anniversary of Pluto's discovery) and use Charon's gravity to adjust its orbit as needed to fulfill science objectives after arriving at the Pluto system. [187] The orbiter could then use Charon's gravity to leave the Pluto system and study more KBOs after all Pluto science objectives are completed. A conceptual study funded by the NASA Innovative Advanced Concepts (NIAC) program describes a fusion-enabled Pluto orbiter and lander based on the Princeton field-reversed configuration reactor. [188][189]
New Horizons imaged all of Pluto's northern hemisphere, and the equatorial regions down to about 30° South. Higher southern latitudes have only been observed, at very low resolution, from Earth. [190] Images from the Hubble Space Telescope in 1996 cover 85% of Pluto and show large albedo features down to about 75° South. [191][192] This is enough to show the extent of the temperate-zone maculae. Later images had slightly better resolution, due to minor improvements in Hubble instrumentation. [193] The equatorial region of the sub-Charon hemisphere of Pluto has only been imaged at low resolution, as New Horizons made its closest approach to the anti-Charon hemisphere. [194]
Some albedo variations in the higher southern latitudes could be detected by New Horizons using Charon-shine (light reflected off Charon). The south polar region seems to be darker than the north polar region, but there is a high-albedo region in the southern hemisphere that may be a regional nitrogen or methane ice deposit. [195]
See also
• How I Killed Pluto and Why It Had It Coming
• List of geological features on Pluto
• Pluto in astrology
• Pluto in fiction
• Stats of planets in the Solar System
Notes
1. This photograph was taken by the Ralph telescope aboard New Horizons on July 14, 2015 from a distance of 35,445 km (22,025 mi)
2. The mean elements here are from the Theory of the Outer Planets (TOP2013) solution by the Institut de mécanique céleste et de calcul des éphémérides (IMCCE). They refer to the standard equinox J2000, the barycenter of the Solar System, and the epoch J2000.
3. Surface area derived from the radius r: $4\pi r^{2}$.
4. Volume v derived from the radius r: $4\pi r^{3}/3$.
5. Surface gravity derived from the mass M, the gravitational constant G and the radius r: $GM/r^{2}$.
6. Escape velocity derived from the mass M, the gravitational constant G and the radius r: ${\sqrt {2GM/r}}$.
7. Based on geometry of minimum and maximum distance from Earth and Pluto radius in the factsheet
8. A French astronomer had suggested the name Pluto for Planet X in 1919, but there is no indication that the Lowell staff knew of this. [28]
9. For example, ⟨♇⟩ (in Unicode: U+2647 ♇ PLUTO) occurs in a table of the planets identified by their symbols in a 2004 article written before the 2006 IAU definition,[32] but not in a graph of planets, dwarf planets and moons from 2016, where only the eight IAU planets are identified by their symbols. [33] (Planetary symbols in general are uncommon in astronomy, and are discouraged by the IAU. )[34]
10. The bident symbol (U+2BD3 ⯓ PLUTO FORM TWO) has seen some astronomical use as well since the IAU decision on dwarf planets, for example in a public-education poster on dwarf planets published by the NASA/JPL Dawn mission in 2015, in which each of the five dwarf planets announced by the IAU receives a symbol. | 12 | 5 |
[36] There are in addition several other symbols for Pluto found in astrological sources,[37] including three accepted by Unicode: , U+2BD4 ⯔ PLUTO FORM THREE, used principally in southern Europe; /, U+2BD6 ⯖ PLUTO FORM FIVE (found in various orientations, showing Pluto's orbit cutting across that of Neptune), used principally in northern Europe; and , U+2BD5 ⯕ PLUTO FORM FOUR, used in Uranian astrology. [38]
11. The equivalence is less close in languages whose phonology differs widely from Greek's, such as Somali Buluuto and Navajo Tłóotoo.
12. The discovery of Charon in 1978 allowed astronomers to accurately calculate the mass of the Plutonian system. But it did not indicate the two bodies' individual masses, which could only be estimated after other moons of Pluto were discovered in late 2005. As a result, because Pluto came to perihelion in 1989, most Pluto perihelion date estimates are based on the Pluto–Charon barycenter. Charon came to perihelion 4 September 1989. The Pluto–Charon barycenter came to perihelion 5 September 1989. Pluto came to perihelion 8 September 1989.
13. Because of the eccentricity of Pluto's orbit, some have theorized that it was once a satellite of Neptune. [94]
14. The dwarf planet Eris is roughly the same size as Pluto, about 2330 km; Eris is 28% more massive than Pluto. Eris is a scattered-disc object, often considered a distinct population from Kuiper-belt objects like Pluto; Pluto is the largest body in the Kuiper belt proper, which excludes the scattered-disc objects.
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Further reading
• Codex Regius (2016), Pluto & Charon, CreateSpace Independent Publishing Platform ISBN 978-1534960749
• Stern, S A and Tholen, D J (1997), Pluto and Charon, University of Arizona Press ISBN 978-0816518401
• Stern, Alan; Grinspoon, David (2018). Chasing New Horizons: Inside the Epic First Mission to Pluto. Picador. ISBN 978-125009896-2.
• Stern, Alan (August 10, 2021). The Pluto System After New Horizons. University of Arizona Press. p. 688. ISBN 978-0816540945.
External links
• New Horizons homepage Archived July 26, 2015, at the Wayback Machine
• Pluto Profile at NASA's Solar System Exploration site
• NASA Pluto factsheet Archived November 19, 2015, at archive.today
• Website of the observatory that discovered Pluto Archived March 2, 2011, at the Wayback Machine
• Earth telescope image of Pluto system
• Keck infrared with AO of Pluto system Archived November 9, 2020, at the Wayback Machine
• Video – Pluto – viewed through the years (GIF) Archived July 26, 2015, at the Wayback Machine (NASA; animation; July 15, 2015).
• Video – Pluto – "FlyThrough" (00:22; MP4) Archived September 29, 2021, at the Wayback Machine (YouTube) Archived December 2, 2020, at the Wayback Machine (NASA; animation; August 31, 2015).
• "A Day on Pluto Video made from July 2015 New Horizon Images" Archived February 23, 2016, at the Wayback Machine Scientific American
• NASA CGI video Archived August 1, 2017, at the Wayback Machine of Pluto flyover (July 14, 2017)
• CGI video Archived October 3, 2020, at the Wayback Machine simulation of rotating Pluto by Seán Doran (see album Archived July 27, 2020, at the Wayback Machine for more)
• Google Pluto 3D Archived August 6, 2020, at the Wayback Machine, interactive map of the dwarf planet
• "Interactive 3D gravity simulation of the Plutonian system". Archived from the original on June 11, 2020.
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• all 28
• Neptune
• Triton
• Proteus
• Nereid
• all 16
• Orcus
• Vanth
• Pluto
• Charon
• Nix
• Hydra
• Kerberos
• Styx
• Haumea
• Hiʻiaka
• Namaka
• Quaoar
• Weywot
• Makemake
• S/2015 (136472) 1
• Gonggong
• Xiangliu
• Eris
• Dysnomia
Rings
• Jovian
• Saturnian (Rhean?)
• Charikloan
• Chironean
• Uranian
• Neptunian
• Haumean
• Quaoarian
Small
Solar
System
bodies
• Comets
• Damocloids
• Meteoroids
• Minor planets
• names and meanings
• moons
• Planetesimal
• Planetary orbit-crossing minor planets
• Mercury
• Venus
• Earth
• Mars
• Jupiter
• Saturn
• Uranus
• Neptune
• Trojans
• Venus
• Earth
• Mars
• Jupiter
• Trojan camp
• Greek camp
• Saturn Moons
• Uranus
• Neptune
• Near-Earth objects
• Asteroid belt
• Asteroids
• Ceres
• Vesta
• Pallas
• Hygiea
• active
• first 1000
• families
• PHA
• exceptional
• Kirkwood gap
• Centaurs
• Neptune trojans
• Trans-Neptunian objects
• Kuiper belt
• Cubewanos
• Plutinos
• Detached objects
• Sednoids
• Scattered disc
• Oort cloud
• Hills cloud
Hypothetical
objects
• Fifth giant
• Nemesis
• Phaeton
• Planet Nine
• Planet V
• Planet X
• Subsatellites
• Theia
• Tyche
• Vulcan
• Vulcanoids
Exploration
(outline)
• Colonization
• Discovery
• astronomy
• historical models
• timeline
• Space probes
• timeline
• list
• Human spaceflight
• space stations
• list
• programs
• Mercury
• Venus
• Moon
• mining
• Mars
• Ceres
• Asteroids
• mining
• Comets
• Jupiter
• Saturn
• Uranus
• Neptune
• Pluto
• Deep space
Formation
and
evolution
• Star formation
• Accretion
• Accretion disk
• Excretion disk
• Circumplanetary disk
• Circumstellar disc
• Circumstellar envelope
• Coatlicue
• Cosmic dust
• Debris disk
• Detached object
• EXCEDE
• Exozodiacal dust
• Extraterrestrial materials
• Sample curation
• Sample-return mission
• Frost/Ice/Snow line
• Giant-impact hypothesis
• Gravitational collapse
• Hills cloud
• Hill sphere
• Interplanetary dust cloud
• Interplanetary medium/space
• Interstellar cloud
• Interstellar medium
• Interstellar space
• Kuiper belt
• Kuiper cliff
• Molecular cloud
• Nebular hypothesis
• Oort cloud
• Outer space
• Planet
• Disrupted
• Migration
• System
• Planetesimal
• Formation
• Merging stars
• Protoplanetary disk
• Ring system
• Roche limit
• vs. Hill sphere
• Rubble pile
• Scattered disc
Lists
• Comets
• Possible dwarf planets
• Gravitationally rounded objects
• Minor planets
• Natural satellites
• Solar System models
• Solar System objects
• by size
• by discovery date
• Interstellar and circumstellar molecules
Related
• Double planet
• Lagrangian points
• Moonlets
• Syzygy
• Tidal locking
• Outline of the Solar System
• Solar System portal
• Astronomy portal
• Earth sciences portal
Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Local Sheet → Virgo Supercluster → Laniakea Supercluster → Local Hole → Observable universe → Universe
Each arrow (→) may be read as "within" or "part of".
New Horizons
• Timeline
• Exploration of Pluto
• List of New Horizons topics
• New Frontiers program
Targets
Flybys
• 132524 APL
• Jupiter
• Pluto
• 486958 Arrokoth
Observations
• Neptune and Triton
• 2011 JY31
• 2011 KW48
• 15810 Arawn
• 28978 Ixion
• 50000 Quaoar
• 136108 Haumea
• 136199 Eris
• 136472 Makemake
• (307261) 2002 MS4
• (516977) 2012 HZ84
• (556416) 2014 OE394
• 2012 HE85
Rejected
• 2011 HM102
• 2014 MT69
• 2014 OS393
• 2014 PN70
Spacecraft
Instruments
• Alice
• Long Range Reconnaissance Imager
• PEPSSI
• Ralph
• REX
• Venetia Burney Student Dust Counter
• SWAP
Subsystems
• GPHS-RTG
Personnel
Institutions
• Applied Physics Laboratory
• Ball Aerospace | 12 | 14 |
• Goddard Space Flight Center
• Jet Propulsion Laboratory
• KinetX
• Southwest Research Institute
• Stanford University
• University of Colorado
People
• Frances Bagenal
• Richard Binzel
• Alice Bowman
• Marc Buie
• Lisa Hardaway
• Brian May
• Cathy Olkin
• Daniel Sarokon
• Mark Showalter
• Alan Stern
• Hal Weaver
Logistics
• Atlas V (launch vehicle)
• Centaur (upper stage)
• Star 48B (3rd stage)
• Cape Canaveral Air Force Station Space Launch Complex 41 (launch site)
• Deep Space Network
Related
• Hubble Space Telescope
• Kuiper belt
• New Horizons 2
• Pluto Kuiper Express
Category
Authority control databases
International
• FAST
National
• Spain
• France
• BnF data
• Germany
• Israel
• United States
• Japan
• Czech Republic
Other
• JPL SBDB
• MPC
• IdRef | 12 | 15 |
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