1957 Angara

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]

1957 Angara
Modelled shape of Angara from its lightcurve
Discovery [1]
Discovered byL. Chernykh
Discovery siteCrimean Astrophysical Obs.
Discovery date1 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 arc60.58 yr (22,126 days)
Aphelion3.1828 AU
Perihelion2.8338 AU
3.0083 AU
Eccentricity0.0580
5.22 yr (1,906 days)
345.36°
0° 11m 20.04s / day
Inclination11.191°
50.702°
209.03°
Physical characteristics
Dimensions17.907±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]

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    References
    1. "JPL Small-Body Database Browser: 1957 Angara (1970 GF)" (2017-06-02 last obs.). Jet Propulsion Laboratory. Retrieved 2 July 2017.
    2. Schmadel, Lutz D. (2007). "(1957) Angara". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 157. doi:10.1007/978-3-540-29925-7_1958. ISBN 978-3-540-00238-3.
    3. "LCDB Data for (1957) Angara". Asteroid Lightcurve Database (LCDB). Retrieved 4 April 2017.
    4. Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 4 April 2017.
    5. Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
    6. Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 17 October 2019. (online, AcuA catalog p. 153)
    7. Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 4 April 2017.
    8. Binzel, R. P. (October 1987). "A photoelectric survey of 130 asteroids". Icarus. 72 (1): 135–208. Bibcode:1987Icar...72..135B. doi:10.1016/0019-1035(87)90125-4. ISSN 0019-1035. Retrieved 4 April 2017.
    9. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 4 April 2017.
    10. "1957 Angara (1970 GF)". Minor Planet Center. Retrieved 4 April 2017.
    11. Schmadel, Lutz D. (2009). "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.
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