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(309239) 2007 RW10, provisionally known as 2007 RW10, is a temporary quasi-satellite of Neptune.[3] Observed from Neptune, it would appear to go around it during one Neptunian year but it actually orbits the Sun, not Neptune.

(309239) 2007 RW10
Discovered byPDSSS
Discovery date9 September 2007
TNO[1] · Nept. co-orbital
centaur · distant
Orbital characteristics[1]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 2
Observation arc10693 days (29.28 yr)
Aphelion39.28320 AU (5.876683 Tm)
Perihelion21.06436 AU (3.151183 Tm)
30.17878 AU (4.514681 Tm)
165.79 yr (60555.1 d)
0° 0m 21.402s / day
Earth MOID20.2499 AU (3.02934 Tm)
Jupiter MOID17.1323 AU (2.56296 Tm)
Physical characteristics
Dimensions247±30 km[2]


Discovery, orbit and physical propertiesEdit

(309239) 2007 RW10 was discovered by the Palomar Distant Solar System Survey on September 9, 2007,[4][5] with precovery images from 1988 (also taken at Palomar).[6] At the time of discovery, this minor body was believed to be a Neptune trojan,[7] but it is no longer listed as such.[8][9] The Jet Propulsion Laboratory classifies (309239) 2007 RW10 as trans-Neptunian object but the Minor Planet Center includes the object among centaurs. It moves in an orbit with an inclination of 36.2°, a semi-major axis of 30.18 AU, and an eccentricity of 0.3020.[1] Herschel-PACS observations indicate that it has a diameter of 247 km.[2]

Quasi-satellite dynamical state and orbital evolutionEdit

(309239) 2007 RW10 is currently following a quasi-satellite loop around Neptune.[3] It has been a quasi-satellite of Neptune for about 12,500 years and it will remain in that dynamical state for another 12,500 years.[3] Prior to the quasi-satellite dynamical state, (309239) 2007 RW10 was an L5 trojan and it will go back to that state soon after leaving its current quasi-satellite orbit. Its orbital inclination is the largest among known Neptune co-orbitals. It is also possibly the largest known object trapped in the 1:1 mean-motion resonance with any major planet.


(309239) 2007 RW10 is a dynamically hot (both, high eccentricity and inclination) object that is unlikely to be a primordial Neptune co-orbital. It probably originated well beyond Neptune and was later temporarily captured in the 1:1 commensurability with Neptune.[3][10]

See alsoEdit

  • 2005 TN74, which was also suspected of being a Neptune trojan at the time of discovery


  1. ^ a b c d "JPL Small-Body Database Browser: 2007 RW10". Retrieved 2018-08-25.
  2. ^ a b c Santos-Sanz, P., Lellouch, E., Fornasier, S., Kiss, C., Pal, A., Müller, T. G., Vilenius, E., Stansberry, J., Mommert, M., Delsanti, A., Mueller, M., Peixinho, N., Henry, F., Ortiz, J. L., Thirouin, A., Protopapa, S., Duffard, R., Szalai, N., Lim, T., Ejeta, C., Hartogh, P., Harris, A. W., & Rengel, M. (2012). “TNOs are Cool”: A Survey of the Transneptunian Region IV - Size/albedo characterization of 15 scattered disk and detached objects observed with Herschel Space Observatory-PACS
  3. ^ a b c d de la Fuente Marcos, C.; de la Fuente Marcos, R. (2012). "(309239) 2007 RW10: a large temporary quasi-satellite of Neptune". Astronomy and Astrophysics Letters. 545: L9. arXiv:1209.1577. Bibcode:2012A&A...545L...9D. doi:10.1051/0004-6361/201219931.
  4. ^ "Discovery MPEC". Retrieved 2012-07-26.
  5. ^ Schwamb, Megan E.; et al. (September 2010). "Properties of the Distant Kuiper Belt: Results from the Palomar Distant Solar System Survey". arXiv:1007.2954. Bibcode:2010ApJ...720.1691S. doi:10.1088/0004-637X/720/2/1691.
  6. ^ "(309239) = 2007 RW10". Retrieved 2018-08-25.
  7. ^ "Distant EKOs, 55". Retrieved 2012-07-24.
  8. ^ "Distant EKOs 56". Retrieved 2012-07-24.
  9. ^ Minor Planet Center List Of Neptune Trojans (2007-12-01)
  10. ^ Horner, J.; Lykawka, P. S.; Bannister, M. T.; Francis, P. (2012). "2008 LC18: a potentially unstable Neptune Trojan". Monthly Notices of the Royal Astronomical Society. 422 (3): 2145–2151. arXiv:1202.3279. Bibcode:2012MNRAS.422.2145H. doi:10.1111/j.1365-2966.2012.20757.x.

External linksEdit