2000 YW134 orbits the Sun at a distance of 41.0–73.8 AU once every 434 years and 9 months (158,805 days; semi-major axis of 57.39 AU). Its orbit has an eccentricity of 0.29 and an inclination of 20° with respect to the ecliptic.[4] The body's observation arc begins with its official discovery observation by Spacewatch on 26 December 2000.[2] It last came to perihelion in 1979,[12] and is currently at about 46.5 AU from the Sun, with an apparent magnitude of 21.54.[11] It will reach aphelion in December 2197.[12]
2000 YW134 is a resonant trans-Neptunian object that stays in a rare 3:8 mean-motion orbital resonance with Neptune, orbiting exactly three times the Sun for every 8 orbits Neptune does.[6] There are currently two other objects known to have the same resonant type: 2014 UE228 and (542258) 2013 AP183.[5][13] Due to its relatively large distance to Neptune, a classification as an extended-scattered or detached object was also considered earlier on (Lykawka, 2006). However, improved observations and long-term numerical integrations of the object's orbit by Emel’yanenko and Kiseleva (84% probability) and the Deep Ecliptic Survey – with all alternative integrations in agreement, showing a minimum perihelion distance of 38.2 AU – have since secured its 3:8 orbital resonance with Neptune.[6][14]
The surface of 2000 YW134 is moderately red in the visible part of the spectrum. Its IR spectral type transitions from the very red (RR) to the intermediate blue-red (BR).[10] Alternatively a BR-spectral type has also been assumed.[7] The object's B−V and V–R color indices have also been measured several times, giving an averaged value of close to 1.0 and 0.5, respectively, for a combined B−R magnitude of 1.50.[9]
Diameter and albedo
In 2010, observations with the Herschel Space Observatory constrained the object's geometric albedo to no darker than 8%, and allowed to place an upper limit on its effective mean diameter of 500 km (310 mi), as no thermal radiation had been detected.[8] However, according to Michael Mommert's dissertation in 2013, the object has a much higher albedo of 0.408±0.329, which greatly reduces its effective diameter to 229 km (140 mi).[7]
Satellite
On 25 October 2002, observations in the far-infrared with the NICMOS instrument of the Hubble Space Telescope revealed that 2000 YW134 is a binary system with a satellite in its orbit. The discovery was announced on 6 October 2005.[7][17]: 22 Johnston's Archive derives a diameter of 216 km (130 mi) for the primary and a diameter of 75 km (47 mi) for the secondary, based on a secondary-to-primary diameter ratio of 0.347, for a difference of 1.3 magnitudes between the two objects. The satellite, designated S/2005 (82075) 1, orbits its primary every 10 days (estimated) at an average distance of 1,900 km (1,200 mi).[7]
