Discovered by E. W. Elst MPC designation 21088 Chelyabinsk Minor planet category Amor · NEO Aphelion 2.11 m Argument of perihelion 27.116° Discovery site La Silla Observatory | Discovery date 30 January 1992 Alternative names 1992 BL2 Discovered 30 January 1992 Inclination 38.46° Discoverer Eric Walter Elst Asteroid group Amor asteroid | |
Named after Chelyabinsk
(city, meteor) | ||
21088 Chelyabinsk, provisional designation 1992 BL2, is a stony asteroid, classified as near-Earth object of the Amor group, approximately 4.2 kilometers in diameter. It was discovered on 30 January 1992, by Belgian astronomer Eric Elst at ESO's La Silla Observatory in northern Chile.
The S-type asteroid is also classified as a Q and L-type. It orbits the Sun at a distance of 1.3–2.1 AU once every 2 years and 3 months (814 days). Its orbit has an eccentricity of 0.24 and an inclination of 38° with respect to the ecliptic. It has an Earth minimum orbit intersection distance of 0.308 AU (46,000,000 km). The first precovery was taken during the Digitized Sky Survey at the Australia Siding Spring Observatory in 1990, extending the asteroid's observation arc by 2 years prior to its discovery.
Two rotational light-curves for this asteroid were obtained by Czech astronomer Petr Pravec at Ondřejov Observatory in December 2002 and September 2004, respectively. They gave a rotation period of 22.490 and 7001224259999999999♠22.426 hours, each with a brightness variation of 0.13 magnitude (U=n.a./3-).
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), the asteroid measures 4.2 kilometers in diameter and its surface has an albedo 0.21, while observations by the Japanese Akari satellite gave a higher albedo of 0.26 and a diameter of 3.5 kilometers, as the higher the albedo, the lower the body's diameter at a constant absolute magnitude. The Collaborative Asteroid Lightcurve Link agrees with the revised results obtained by WISE, taking a diameter of 4.23 kilometers with an albedo of 0.179, based on an absolute magnitude of 14.35.
The minor planet is named after the Russian city Chelyabinsk, located in the Urals, Siberia. The city is well known for the Chelyabinsk meteor, a 20-meter sized, extremely bright fireball that exploded to the south of the city at an altitude of 30 kilometers on 15 February 2013. The indirect effects of the explosion injured more than 1,500 people. Naming citation was published on 21 August 2013 (M.P.C. 84674).