(148975) 2001 XA255

Centaur yes #C7FF8F (148975) 2001 XA 255 David C. Jewitt, Scott S. Sheppard and Jan Kleyna 9 December 2001 (148975) 2001 XA 255 Centaur 13 January 2016 (JD 2457400.5) 48.731 AU Tm on on 9.3364 AU Tm on 29.034 AU Tm on 0.67843 156.44 yr (57141.1 d) 12.628° 105.89° 12.809° 90.452° 12.5 km38 km 0.041 11.1 0.0063002 ms / day 3812 days (10.44 yr) 2 4.12722 AU Gm on (148975) 2001 XA 255 is a dark minor planet in the outer Solar System, classified as centaur, approximately 38 km mi off 2 us in diameter. It was discovered on 9 December 2001, by David C. Jewitt, Scott S. Sheppard, and Jan Kleyna observing from the Mauna Kea Observatory. The object is currently trapped in a 1:1 mean-motion resonance with Neptune following a path of the horseshoe type. Orbit and classification 2001 XA 255 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. Resonance with Neptune 2001 XA 255 was identified as trapped in a 1:1 mean-motion resonance with Neptune and 1:2 with Uranus by T. Gallardo in 2006. 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. Physical characteristics The object has an estimated diameter of 12.5 km and it was classified as an inactive centaur by David Jewitt. Observations by the NEOWISE mission gave a larger diameter of 37.7 kilometers and an albedo of 0.041. It has an absolute magnitude is 11.1. See also List of centaurs (small Solar System bodies) 148975 References https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=148975;cad=1 148975 (2001 XA255) JPL Small-Body Database NASA/Jet Propulsion Laboratory 7 April 2016 ADS link Gallardo, T. (2006) Atlas of the mean-motion resonances in the Solar System Jewitt David C. Sheppard S. S. Kleyna J. Marsden B. G. 2001 XA255 Minor Planet Electronic Circular de la Fuente Marcos C. de la Fuente Marcos R. Four temporary Neptune co-orbitals: (148975) 2001 XA255, (310071) 2010 KR59, (316179) 2010 EN65, and 2012 GX17 Astronomy and Astrophysics 547 L2 2012 10.1051/0004-6361/201220377 2012A&A...547L...2D 1210.3466 118622987 Jewitt David C. The Active Centaurs The Astronomical Journal 137 5 4296–4312 2009 10.1088/0004-6256/137/5/4296 2009AJ....137.4296J 0902.4687 18877930 List of Known Trans-Neptunian Objects Johnston's Archive 18 August 2020 Johnston Wm. Robert http://www.johnstonsarchive.net/astro/tnoslist.html 12 August 2021 External links 2001 XA255, Jewitt, D. C., Sheppard, S. S., Kleyna, J., & Marsden, B. G. 2002, Minor Planet Electronic Circular, 2002-A85. The Active Centaurs, Jewitt, D. C. 2009, Astronomical Journal, Volume 137, Number 5, pp. 4296–4312. (148975) 2001 XA 255 data at MPC Atlas of the mean motion resonances in the Solar System Gallardo, T. 2006, Icarus, Volume 184, Issue 1, pp. 29–38. Four temporary Neptune co-orbitals: (148975) 2001 XA255, (310071) 2010 KR59, (316179) 2010 EN65, and 2012 GX17 de la Fuente Marcos, C., & de la Fuente Marcos, R. 2012, Astronomy and Astrophysics, Volume 547, id.L2, 7 pp. IAU list of centaurs and scattered-disk objects IAU list of trans-neptunian objects Another list of TNOs 148975 148975 (148975) 2001 XA 255 Category:Neptune co-orbital minor planets Category:Centaurs (small Solar System bodies) Category:Discoveries by David C. Jewitt Category:Discoveries by Scott S. Sheppard Category:Discoveries by Jan Kleyna 20011209