617 Patroclus: Difference between revisions
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==Binary system== |
==Binary system== |
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In 2001, it was discovered that Patroclus is a [[binary asteroid|binary]] object, made up of two components of roughly similar size.<ref name="Johnston"/><ref name="Merline">{{Citation| last=Merline| first=W. J.| year=2001| url=http://www.cbat.eps.harvard.edu/iauc/07700/07741.html| title=IAUC 7741: 2001fc; S/2001 (617) 1; C/2001 T1, C/2001 T2}}</ref><ref name="IAU-list">{{cite web |date=2009-09-17 |title=Satellites and Companions of Minor Planets |publisher=IAU / [[Central Bureau for Astronomical Telegrams|CBAT]] |url=http://www.cbat.eps.harvard.edu/minorsats.html |accessdate=2011-01-25}}</ref> In 2006, accurate measurements of the orbit from the [[Keck telescopes|Keck]] [[Laser guide star]] [[adaptive optics]] system were reported.<ref name="Marchis2006"/> It was estimated<ref name="Sanders">{{Citation| last=Sanders| first=Robert| year=2006| url=http://www.berkeley.edu/news/media/releases/2006/02/01_patroclus.shtml| title=Binary asteroid in Jupiter's orbit may be icy comet from solar system's infancy| publisher=[[University of California, Berkeley]]}}</ref> that the two components orbit around their [[center of mass]] in 4.283±0.004 d at a distance of 680±20 km, describing a roughly circular orbit.<ref name="Johnston"/> Combining these observations with thermal measurements taken in 2000, the sizes of the components of the system were estimated. The slightly larger component, which measures |
In 2001, it was discovered that Patroclus is a [[binary asteroid|binary]] object, made up of two components of roughly similar size.<ref name="Johnston"/><ref name="Merline">{{Citation| last=Merline| first=W. J.| year=2001| url=http://www.cbat.eps.harvard.edu/iauc/07700/07741.html| title=IAUC 7741: 2001fc; S/2001 (617) 1; C/2001 T1, C/2001 T2}}</ref><ref name="IAU-list">{{cite web |date=2009-09-17 |title=Satellites and Companions of Minor Planets |publisher=IAU / [[Central Bureau for Astronomical Telegrams|CBAT]] |url=http://www.cbat.eps.harvard.edu/minorsats.html |accessdate=2011-01-25}}</ref> In 2006, accurate measurements of the orbit from the [[Keck telescopes|Keck]] [[Laser guide star]] [[adaptive optics]] system were reported.<ref name="Marchis2006"/> It was estimated<ref name="Sanders">{{Citation| last=Sanders| first=Robert| year=2006| url=http://www.berkeley.edu/news/media/releases/2006/02/01_patroclus.shtml| title=Binary asteroid in Jupiter's orbit may be icy comet from solar system's infancy| publisher=[[University of California, Berkeley]]}}</ref> that the two components orbit around their [[center of mass]] in 4.283±0.004 d at a distance of 680±20 km, describing a roughly circular orbit.<ref name="Johnston"/> Combining these observations with thermal measurements taken in 2000, the sizes of the components of the system were estimated. The slightly larger component, which measures 141 km in diameter, retains the name Patroclus.<ref name="Johnston"/> The smaller component, measuring 112 km, is now named Menoetius,<ref name="Johnston"/> after the legendary Patroclus's father. Its [[provisional designation]] was '''S/2001 (617) 1'''. |
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==Composition== |
==Composition== |
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Revision as of 21:05, 26 May 2014
| Discovery | |
|---|---|
| Discovered by | August Kopff |
| Discovery date | October 17, 1906 |
| Designations | |
Named after | Patroclus |
| 1906 VY; 1941 XC; 1962 NB | |
| Jupiter trojan | |
| Adjectives | Patroclean |
| Orbital characteristics[1] | |
| Epoch 2455800.5 (JD 2011-Aug-27.0) | |
| Aphelion | 5.9481823 AU |
| Perihelion | 4.4878688 AU |
| 5.2180256 AU | |
| Eccentricity | 0.1399297 |
| 11.9197598 a (4353.6923 d) | |
| 331.77002° | |
| Inclination | 22.05276° |
| 44.36649° | |
| 307.90775° | |
| Physical characteristics | |
| Dimensions | 143.14 ± 8.37[2] km |
| Mass | (1.36 ± 0.11) × 1018[2] kg |
Mean density | 0.88 ± 0.17[2] g/cm3 |
| >4.283±0.004 days | |
| Albedo | 0.047 |
| Temperature | 110 K |
Spectral type | P-type |
| 8.19 | |
617 Patroclus (/pəˈtroʊkləs/ pə-TROH-kləs) is a binary minor planet made up of two objects of similar size orbiting their common centre of gravity. It is a Jupiter trojan. It was discovered in 1906 by August Kopff, and was the second trojan to be discovered.[3] Its binary nature was discovered in 2001; the name Patroclus now refers to the larger of the two components, whereas its slightly smaller companion body has been named Menoetius (/m[invalid input: 'ɨ']ˈniːʃəs/ mə-NEE-shəs, official designation (617) Patroclus I Menoetius). Recent evidence suggests that the objects are icy like comets, rather than rocky like most asteroids.
Orbit
Patroclus orbits in Jupiter's trailing Lagrangian point, L5,[3] in an area called the 'Trojan node' after one of the sides in the legendary Trojan War (the other node, at the L4 point, is called the 'Greek node'). Patroclus is the only object in the Trojan camp to be named after a Greek character; the naming conventions for the Jupiter trojans were not adopted until after Patroclus was named (similarly, the asteroid Hektor is the only Trojan character to appear in the Greek camp).
Binary system
In 2001, it was discovered that Patroclus is a binary object, made up of two components of roughly similar size.[3][4][5] In 2006, accurate measurements of the orbit from the Keck Laser guide star adaptive optics system were reported.[6] It was estimated[7] that the two components orbit around their center of mass in 4.283±0.004 d at a distance of 680±20 km, describing a roughly circular orbit.[3] Combining these observations with thermal measurements taken in 2000, the sizes of the components of the system were estimated. The slightly larger component, which measures 141 km in diameter, retains the name Patroclus.[3] The smaller component, measuring 112 km, is now named Menoetius,[3] after the legendary Patroclus's father. Its provisional designation was S/2001 (617) 1.
Composition
Because of the density of the components (0.8 g/cm³) is less than water and about one third that of rock, it was suggested that the Patroclus system, previously thought to be a pair of rocky asteroids, is more similar to a comet in composition.[6] It is suspected that many Jupiter trojans are in fact small planetesimals captured in the Lagrange point of Jupiter–Sun system during the migration of the giant planets 3.9 billion years ago. This scenario was proposed by A. Morbidelli and colleagues in a series of articles published in May 2005 in Nature.[8]
See also
References
- ^ JPL Small-Body Database Browser Retrieved 2011-08-30
- ^ a b c Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
- ^ a b c d e f Johnston, Wm. Robert (2006), (617) Patroclus and Menoetius
- ^ Merline, W. J. (2001), IAUC 7741: 2001fc; S/2001 (617) 1; C/2001 T1, C/2001 T2
- ^ "Satellites and Companions of Minor Planets". IAU / CBAT. 2009-09-17. Retrieved 2011-01-25.
- ^ a b Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1038/nature04350, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with
|doi=10.1038/nature04350instead. - ^ Sanders, Robert (2006), Binary asteroid in Jupiter's orbit may be icy comet from solar system's infancy, University of California, Berkeley
- ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1038/nature03540, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with
|doi=10.1038/nature03540instead.