1881 Shao
Main-belt asteroid
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1881 Shao, provisional designation 1940 PC or 1968 OO, is a background asteroid from the outer regions of the asteroid belt, approximately 25 kilometers (16 miles) in diameter. It was discovered on 3 August 1940, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany.[1] The presumed C-type asteroid has a rotation period of 7.45 hours.[7] It was named for Chinese astronomer Cheng-yuan Shao.[1]
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 3 August 1940 |
| Designations | |
| (1881) Shao | |
Named after | Cheng-yuan Shao[1] (Chinese astronomer) |
| 1940 PC · 1968 OO | |
| main-belt[1][2] · (outer) background[3] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 77.71 yr (28,385 d) |
| Aphelion | 3.5061 AU |
| Perihelion | 2.8339 AU |
| 3.1700 AU | |
| Eccentricity | 0.1060 |
| 5.64 yr (2,062 d) | |
| 314.29° | |
| 0° 10m 28.56s / day | |
| Inclination | 9.8706° |
| 218.07° | |
| 66.640° | |
| Physical characteristics | |
| 24.083±0.134 km[4] 25.437±0.176 km[5] 25.46±0.86 km[6] 29.21 km (calculated)[7] | |
| 5.61±0.07 h[8] 7.452±0.002 h[9] | |
| 0.057 (assumed)[7] 0.0994±0.0087[5] 0.111±0.010[4] 0.115±0.009[6] | |
| C (assumed)[7] | |
| 11.10[5][6] 11.19±0.04 (R)[8] 11.4[2][7] 11.65±0.25[10] | |
Orbit and classification
Shao is a non-family asteroid from the main belt's background population.[3] It orbits the Sun in the outer main-belt at a distance of 2.8â3.5 AU once every 5 years and 8 months (2,062 days; semi-major axis of 3.17 AU). Its orbit has an eccentricity of 0.11 and an inclination of 10° with respect to the ecliptic.[2] The body's observation arc begins with its official discovery observation at Heidelberg in 1940.[1]
Physical characteristics
Shao is an assumed carbonaceous C-type asteroid.[7]
Rotation period
In July 2013, a rotational lightcurve of Shao was obtained from photometric observations by Italian amateur astronomer Silvano Casulli. Lightcurve analysis gave a rotation period of 7.452 hours with a brightness variation of 0.15 magnitude (U=2).[9] A second lightcurve by astronomers at the Palomar Transient Factory from December 2014, gave a shorter period of 5.61 hours and an amplitude of 0.11 (U=2), indicative for a rather spherical shape.[7][8]
Diameter and albedo
According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Shao measures between 24.083 and 25.46 kilometers in diameter and its surface has an albedo between 0.0994 and 0.115.[4][5][6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057, and calculates a diameter of 29.21 kilometers based on an absolute magnitude of 11.4.[7]
Naming
This minor planet was named after Chinese astronomer Cheng-yuan Shao (born 1927), an assistant to Richard McCrosky (see previously numbered 1880 McCrosky) in Harvard's minor-planet program at the HarvardâSmithsonian Center for Astrophysics and Oak Ridge Observatory in Massachusetts, United States. Shao was also involved in the recovery of near-Earth asteroid 1862 Apollo.[1] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3936).[11]
