(148975) 2001 XA255 explained

Minorplanet:yes
Background:
  1. C7FF8F
Discoverer:David C. Jewitt, Scott S. Sheppard and Jan Kleyna
Discovered:9 December 2001
Epoch:13 January 2016 (JD 2457400.5)
Aphelion:48.731abbr=onNaNabbr=on
Perihelion:9.3364AU
Semimajor:29.034AU
Eccentricity:0.67843
Period:156.44 yr (57141.1 d)
Inclination:12.628°
Asc Node:105.89°
Mean Anomaly:12.809°
Arg Peri:90.452°
Mean Diameter:12.5 km
38 km
Albedo:0.041
Abs Magnitude:11.1
Mean Motion: / day
Observation Arc:3812 days (10.44 yr)
Uncertainty:2
Jupiter Moid:4.12722AU

, provisional designation:, is a dark minor planet in the outer Solar System, classified as centaur, approximately 38km (24miles) 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

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

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.

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