| Discovery[1] | |
|---|---|
| Discovered by | E. W. Elst |
| Discovery site | La Silla Obs. |
| Discovery date | 30 January 1992 |
| Designations | |
| (21088) Chelyabinsk | |
Named after | Chelyabinsk[2](city andmeteor) |
| 1992 BL2 | |
| NEO · Amor[1][2] Mars-crosser | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 27.41 yr (10,012 days) |
| Aphelion | 2.1135AU |
| Perihelion | 1.2996 AU |
| 1.7065 AU | |
| Eccentricity | 0.2384 |
| 2.23yr (814 days) | |
| 318.92° | |
| 0° 26m 31.56s / day | |
| Inclination | 38.455° |
| 297.85° | |
| 27.133° | |
| Earth MOID | 0.3083 AU · 120.1LD |
| Physical characteristics | |
| Dimensions | 2.79±0.10 km[3] 3.46±0.25 km[4] 4.23 km(taken)[5] 4.231±0.113 km[6][7] 4.232 km[8] |
| 22.426±0.02h[a][b] 22.49 h[a] | |
| 0.1794[8] 0.206[6] 0.257±0.038[4] 0.26±0.32[9] 0.37±0.06[3] | |
| Q[10] · L[11] · S[5] B–V =0.855±0.073[12] V–R =0.464±0.015[12] V–I =0.910±0.032[12] | |
| 13.86±0.14(R)[a] · 14.00[11] · 14.2[6] · 14.29±0.24[13] · 14.3[1] · 14.35±0.149[5][8] · 14.40[4] | |
21088 Chelyabinsk (provisional designation1992 BL2) is a stonyasteroid andnear-Earth object of theAmor group, approximately 4 kilometers in diameter. It was discovered on 30 January 1992, by Belgian astronomerEric Elst atESO'sLa Silla Observatory in northern Chile. The asteroid was named after the Russian city ofChelyabinsk and for its spectacularChelyabinsk meteor event in 2013.[2] It is not related to the Chelyabinsk impactor.
Chelyabinsk orbits the Sun at a distance of 1.3–2.1 AU once every 2 years and 3 months (814 days). Its orbit has aneccentricity of 0.24 and aninclination of 38° with respect to theecliptic. A firstprecovery was taken during theDigitized Sky Survey at the AustraliaSiding Spring Observatory in January 1990, extending the asteroid'sobservation arc by 2 years prior to its official discovery at La Silla.[2]
As anear-Earth object, Chelyabinsk has a low Earthminimum orbit intersection distance of 0.3083 AU (46,100,000 km), which translates into 120.1lunar distances (LD). This is, however, far too large to make it apotentially hazardous asteroid, which have intersection distances of less than 20 LD.[1] It also crosses the orbit of Mars at 1.666 AU which makes it aMars-crossing asteroid. In August 2142, it will approach Mars at 0.0986 AU (14,800,000 km).[1]
Chelyabinsk has been characterized as both aQ-type andL-type asteroid.[10][11] It is also a generically assumedS-type asteroid.[5]
Two rotationallight-curves of Chelyabinsk were obtained by Czech astronomerPetr Pravec atOndřejov Observatory in December 2002 and September 2004, respectively. They gave arotation period of 22.490 and22.426 hours, each with a brightness variation of 0.13magnitude (U=n.a./3-).[a][b]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE), Chelyabinsk measures between 2.79 and 4.2 kilometers in diameter and its surface has analbedo between 0.21 and 0.37,[6][7][8] while observations by the JapaneseAkari satellite gave an albedo of 0.26 and a diameter of 3.5 kilometers.[4] TheCollaborative Asteroid Lightcurve Link adopts Petr Pravec's revised WISE results, that is, a diameter of 4.23 kilometers and an albedo of 0.179 based on anabsolute magnitude of 14.35.[5][8]
Thisminor planet is named after the Russian cityChelyabinsk, located in theUral region. The city is well known for theChelyabinsk meteor, a 20-meter sized, extremely brightfireball 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.[2] The official naming citation was published by theMinor Planet Center (MPC) on 21 August 2013 (M.P.C. 84674).[14]
Originally, the name "Chelyabinsk" was erroneously given by the MPC to the numerically similar asteroid(20188) 1997 AC18 on 22 July (M.P.C. 84379). The wrong designation20188 Chelyabinsk was deleted in the subsequent publication of theMinor Planet Circulars on 21 August 2013 (M.P.C. 84385)[14]
