1957 Angara
Main-belt asteroid
From Wikipedia, the free encyclopedia
1957 Angara (prov. designation: 1970 GF) is a stony Eos asteroid from the outer regions of the asteroid belt, approximately 18 kilometers (11 miles) in diameter. It was discovered on 1 April 1970, by Soviet astronomer Lyudmila Chernykh at the Crimean Astrophysical Observatory in Nauchnyj, and named after the Siberian Angara River.[2][10]
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Modelled shape of Angara from its lightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | L. Chernykh |
| Discovery site | Crimean Astrophysical Obs. |
| Discovery date | 1 April 1970 |
| Designations | |
| (1957) Angara | |
Named after | Angara River (Siberian river)[2] |
| 1970 GF · 1962 WG1 1969 AA | |
| main-belt · Eos[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 60.58 yr (22,126 days) |
| Aphelion | 3.1828 AU |
| Perihelion | 2.8338 AU |
| 3.0083 AU | |
| Eccentricity | 0.0580 |
| 5.22 yr (1,906 days) | |
| 345.36° | |
| 0° 11m 20.04s / day | |
| Inclination | 11.191° |
| 50.702° | |
| 209.03° | |
| Physical characteristics | |
| Dimensions | 17.907±0.108 km[4] 18.189±0.229 km[5] 18.38 km (derived)[3] 21.44±0.70 km[6] 30.41±0.58 km[7] |
| 3.67 h[8] | |
| 0.055±0.006[7] 0.111±0.008[6] 0.14 (assumed)[3] 0.1438±0.0310[5] | |
| S[3][8] B–V = 0.900[1] U–B = 0.380[1] | |
| 11.16±0.34[9] · 11.36[1][6][7] · 11.43[3][5][8] | |
Classification and orbit
Angara is a member of the Eos family, well known for mostly being of a silicaceous composition. It orbits the Sun in the outer main-belt at a distance of 2.8–3.2 AU once every 5 years and 3 months (1,906 days). Its orbit has an eccentricity of 0.06 and an inclination of 11° with respect to the ecliptic.[1] A first precovery was taken at Goethe Link Observatory in 1956, extending the body's observation arc by 14 years prior to its official discovery observation at Nauchnyj.[10]
Naming
This minor planet was named for the over 1000-mile long Siberian Angara River that drains Lake Baikal.[2] The official naming citation was published by the Minor Planet Center on 30 June 1977 (M.P.C. 4190).[11]
Physical characteristics
In December 1983, a rotational lightcurve of Angara was obtained from photometric observations by American astronomer Richard Binzel. Lightcurve analysis gave a well-define rotation period of 3.67 hours with a brightness amplitude of 0.52 magnitude, indicative of a non-spheroidal shape (U=3).[8] Binzel also classified the body as a stony S-type asteroid.[8]
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Angara measures between 17.907 and 30.41 kilometers in diameter and its surface has an albedo between 0.055 and 0.1438.[4][5][6][7] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony Eoan asteroids of 0.14 – taken from the family's largest member and namesake, 221 Eos – and derives a diameter of 18.38 kilometers with an absolute magnitude of 11.43.[3]
