(provisional designation ) is a centaur orbiting the Sun between Saturn and Neptune in the outer Solar System. It is one of the largest known centaurs, having a highly elongated shape that spans across its longest width to across its shortest. The object was discovered on 13 April 2002 by astronomers at Mauna Kea Observatory in Hawaiûi.
Due to 's highly elongated shape, its apparent brightness oscillates as it rotates every 5.8 hours. has a dark gray surface that potentially contains water ice. It was the third centaur whose stellar occultation has been simultaneously observed by multiple people, after 10199 Chariklo and 2060 Chiron.
was discovered on 13 April 2002 by astronomers at Mauna Kea Observatory in Hawaiûi. The observatory's 8.2-meter Subaru Telescope and University of Hawaiûi 2.24-meter telescope were used for the discovery of . Astronomers involved in the discovery included Jana Pittichová, S. Ash, Karen Meech, James Bauer, David C. Jewitt, Richard Wainscoat, Daisuke Kinoshita, Junichi Watanabe, Tetsuharu Fuse, Marc Buie, Scott Sheppard, and N. Yamamoto. The discovery of this object was announced by the Minor Planet Center (MPC) on 18 May 2002, after the object was reobserved in the same month. In 2007, astronomer Andrew Lowe reported precovery observations of in Palomar Observatory's Digitized Sky Survey images from March 1995 and May 1996, which helped improve calculations of the object's orbit. These precovery observations remain as the earliest known detections of .
This object has the minor planet provisional designation , which was given by the MPC in the discovery announcement. The provisional designation indicates the year and half-month of the object's discovery date. received its permanent minor planet catalog number of 95626 from the MPC on 28 October 2004.
does not have a proper name; more than ten years has passed since the object was numbered, so the discoverers no longer have an exclusive privilege for naming this object. According to naming guidelines by the International Astronomical Union's Working Group for Small Bodies Nomenclature, should be named after a mythological centaur because it orbits between Jupiter and Neptune.
orbits the Sun between Saturn and Neptune with an average orbital distance of 23 astronomical units (AU) and an orbital period of 110 years. It follows an elliptical orbit that crosses paths with Uranus, bringing the object within from the Sun at perihelion to as far as at aphelion. The orbit of is inclined by roughly 15ð with respect to the ecliptic or the orbital plane of the planets. is classified as a centaur, a type of small Solar System body generally defined as orbiting between Jupiter and Neptune. Centaurs are believed to be primitive progenitors of short-period comets, originating from the scattered disc beyond Neptune.
is a highly elongated object with estimated ellipsoid dimensions of . Its size may be represented with an area equivalent diameter of , which would make it one of the largest known centaurs after 10199 Chariklo and 2060 Chiron. The shape of was revealed to astronomers when it occulted or passed in front of a star on 20 May 2017. This occultation event was simultaneously observed by 6 out of 29 different telescopes across Europe, which allowed astronomers to map out the silhouette of 's shape for the first time. was the third centaur whose stellar occultation has been simultaneously observed by multiple people, after 10199 Chariklo and 2060 Chiron.
Observations from 2007 and 2017 showed that 's apparent brightness oscillates sinusoidally with a double-peak period of 5.8 hours. The rotation of 's elongated body causes these brightness variations, so the observed double-peak period is equal to 's rotation period. The minimum degree of elongation suggested by 's brightness variations (a/b 1.13 for ÃÂm 0.13 magnitudes) does not match the actual shape seen in the 2017 occultation, which indicates that the object's rotation axis must be tilted with respect to Earth's line of sight. Analysis of the 2017 occultation data suggests that the aspect angle between 's rotation axis and Earth's line of sight was most likely 76ð.
The observed shape and rotation period of do not match theoretical predictions for a purely self-gravitating body, which means that is not in hydrostatic equilibrium. This is expected because is likely too small to be in hydrostatic equilibrium.
is a dark gray object whose surface potentially contains water ice. It has a low geometric albedo of about 4%, similar to many other centaurs.
Radio telescope observations from 2002 found no signs of carbon monoxide (CO) outgassing from , which places an upper limit CO production rate of molecules per second. Observations of the 20 May 2017 stellar occultation by showed no dense rings or debris surrounding the object, although thin rings with radial widths narrower than about a kilometer have not been ruled out.