_Ahrensa.png) Modelled shape of Ahrensa from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 1 April 1921 |
| Designations | |
| (950) Ahrensa | |
Named after | Ahrens family (friends of discoverer)[2] |
| 1921 JP · 1955 SU2 1974 VG3 · A904 RF | |
| main-belt · Phocaea[3] | |
| Orbital characteristics[1] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 111.60 yr (40761 days) |
| Aphelion | 2.7477 AU (411.05 Gm) |
| Perihelion | 1.9958 AU (298.57 Gm) |
| 2.3717 AU (354.80 Gm) | |
| Eccentricity | 0.15851 |
| 3.65yr (1334.1d) | |
| 53.005° | |
| 0° 16m 11.424s / day | |
| Inclination | 23.477° |
| 181.81° | |
| 348.19° | |
| Physical characteristics | |
| 15.03±1.8(IRAS:15) km[4] 16.21±0.53 km[5] 14.299±0.070 km[6] 16.66±0.41 km[7] 15.34 km(derived)[3] | |
| 202±1h,[8] 202 h (8.4 d)[1] | |
| 0.1793±0.054(IRAS:15)[1][4] 0.158±0.011[5] 0.1988±0.0203[6] 0.231±0.031[7] 0.2727(derived)[3] | |
| SMASS = Sa S[3] | |
| 11.2[1] | |
950 Ahrensa, provisional designation1921 JP, is a stony Phocaeaasteroid andslow rotator from the inner regions of theasteroid belt, approximately 15 kilometers in diameter. It was discovered on 1 April 1921, by German astronomerKarl Reinmuth atHeidelberg Observatory in southern Germany.[9]
TheS-type asteroid, classified as a Sa-subtype in theSMASS taxonomic scheme, is a member of thePhocaea family, a group of asteroids with similar orbital characteristics. It orbits the Sun at a distance of 2.0–2.7 AU once every 3 years and 8 months (1,334 days). Its orbit shows aneccentricity of 0.16 and istilted by 23 degrees to the plane of theecliptic.
A photometriclightcurve analysis at the U.S. Palmer Divide Observatory in 2009, showed that the body has an exceptionally longrotation period of 202 hours.[8] According to the surveys carried out by the Infrared Astronomical Satellite,IRAS, the JapaneseAkari satellite, and the U.S.Wide-field Infrared Survey Explorer with its subsequentNEOWISE mission, the surface of the asteroid has analbedo in the range of 0.16 to 0.23, while the Collaborative Asteroid Lightcurve Link derives an even higher value of 0.27 for the stony body.[3][4][5][6][7]
The minor planet was named in honor of friends of the discoverer Karl Reinmuth, the Ahrens family, who helped him financially at the Heidelberg Observatory. Reinmuth also named the minor planet909 Ulla after Ulla Ahrens, a member of this family.[2]
