(148975) 2001 XA255

(148975) 2001 XA255
Discovered byDavid C. Jewitt, Scott S. Sheppard and Jan Kleyna
Discovery date9 December 2001
(148975) 2001 XA255
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 2
Observation arc3812 days (10.44 yr)
Aphelion48.731 AU (7.2901 Tm)
Perihelion9.3364 AU (1.39671 Tm)
29.034 AU (4.3434 Tm)
156.44 yr (57141.1 d)
0° 0m 22.681s / day
Jupiter MOID4.12722 AU (617.423 Gm)
Physical characteristics
Mean diameter
12.5 km[2]
38 km[1][3]

(148975) 2001 XA255, provisional designation: 2001 XA255, is a dark minor planet in the outer Solar System, classified as centaur, approximately 38 kilometers (24 miles) in diameter.[1] It was discovered on 9 December 2001, by David C. Jewitt, Scott S. Sheppard, and Jan Kleyna observing from the Mauna Kea Observatory.[4] The object is currently trapped in a 1:1 mean-motion resonance with Neptune following a path of the horseshoe type.[5]

Orbit and classification[]

2001 XA255 follows a very eccentric orbit (0.68) with perihelion just inside the orbit of Saturn, aphelion in the trans-Neptunian belt and a semi-major axis of 28.9 AU. The orbital inclination of this object is moderate at 12.6º.[1]

Resonance with Neptune[]

2001 XA255 was identified as trapped in a 1:1 mean-motion resonance with Neptune and 1:2 with Uranus by T. Gallardo in 2006.[6] The object is dynamically unstable and it entered the region of the giant planets relatively recently, perhaps 50,000 years ago, from the scattered disk. It follows a short-lived horseshoe orbit around Neptune.[5]

Physical characteristics[]

The object has an estimated diameter of 12.5 km and it was classified as an inactive centaur by David Jewitt.[2] Observations by the NEOWISE mission gave a larger diameter of 37.7 kilometers and an albedo of 0.041.[3] It has an absolute magnitude is 11.1.[1]

See also[]


  1. ^ a b c d e f g "148975 (2001 XA255)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 7 April 2016.
  2. ^ a b Jewitt, David C. (2009). "The Active Centaurs". The Astronomical Journal. 137 (5): 4296–4312. arXiv:0902.4687. Bibcode:2009AJ....137.4296J. doi:10.1088/0004-6256/137/5/4296. S2CID 18877930.
  3. ^ a b c Johnston, Wm. Robert (18 August 2020). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 12 August 2021.
  4. ^ Jewitt, David C.; Sheppard, S. S.; Kleyna, J.; Marsden, B. G. "2001 XA255". Minor Planet Electronic Circular.
  5. ^ a b de la Fuente Marcos, C.; de la Fuente Marcos, R. (2012). "Four temporary Neptune co-orbitals: (148975) 2001 XA255, (310071) 2010 KR59, (316179) 2010 EN65, and 2012 GX17". Astronomy and Astrophysics. 547: L2. arXiv:1210.3466. Bibcode:2012A&A...547L...2D. doi:10.1051/0004-6361/201220377. S2CID 118622987.
  6. ^ ADS link Gallardo, T. (2006) Atlas of the mean-motion resonances in the Solar System

External links[]