| 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 | 77.71yr (28,385 d) |
| Aphelion | 3.5061AU |
| 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] | |
1881 Shao, provisional designation1940 PC or1968 OO, is a backgroundasteroid from the outer regions of theasteroid belt, approximately 25 kilometers (16 miles) in diameter. It was discovered on 3 August 1940, by German astronomerKarl Reinmuth at theHeidelberg Observatory in southwest Germany.[1] The presumedC-type asteroid has arotation period of 7.45 hours.[7] It was named for Chinese astronomerCheng-yuan Shao.[1]
Shao is a non-family asteroid from the main belt'sbackground population.[3] It orbits the Sun in theouter main-belt at a distance of 2.8–3.5 AU once every 5 years and 8 months (2,062 days;semi-major axis of 3.17 AU). Its orbit has aneccentricity of 0.11 and aninclination of 10° with respect to theecliptic.[2] The body'sobservation arc begins with its official discovery observation at Heidelberg in 1940.[1]
Shao is an assumed carbonaceousC-type asteroid.[7]
In July 2013, a rotationallightcurve ofShao was obtained fromphotometric observations by Italian amateur astronomerSilvano Casulli. Lightcurve analysis gave arotation period of 7.452 hours with a brightness variation of 0.15magnitude (U=2).[9] A second lightcurve by astronomers at thePalomar 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]
According to the surveys carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Shao measures between 24.083 and 25.46 kilometers in diameter and its surface has analbedo between 0.0994 and 0.115.[4][5][6] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057, and calculates a diameter of 29.21 kilometers based on anabsolute magnitude of 11.4.[7]
Thisminor planet was named after Chinese astronomerCheng-yuan Shao (born 1927), an assistant to Richard McCrosky(see previously numbered1880 McCrosky) inHarvard's minor-planet program at theHarvard–Smithsonian Center for Astrophysics andOak Ridge Observatory in Massachusetts, United States. Shao was also involved in the recovery of near-Earth asteroid1862 Apollo.[1] The officialnaming citation was published by theMinor Planet Center on 20 February 1976 (M.P.C. 3936).[11]
