1720 Niels
Main-belt asteroid
From Wikipedia, the free encyclopedia
1720 Niels, provisional designation 1935 CQ, is a stony asteroid from the inner regions of the asteroid belt, approximately 6.4 kilometers in diameter. It was discovered on 7 February 1935, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany, and named after a grandson of the discoverer.[2][9]
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 7 February 1935 |
| Designations | |
| (1720) Niels | |
Named after | Niels (discoverer's grandson)[2] |
| 1935 CQ · 1940 WH 1951 AL · 1953 VO1 1959 RA · 1963 WE | |
| main-belt · (inner)[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 89.52 yr (32,697 days) |
| Aphelion | 2.4170 AU |
| Perihelion | 1.9593 AU |
| 2.1881 AU | |
| Eccentricity | 0.1046 |
| 3.24 yr (1,182 days) | |
| 240.21° | |
| Inclination | 0.7301° |
| 127.86° | |
| 308.86° | |
| Physical characteristics | |
| Dimensions | 6.394±0.091[4] 6.566±0.063 km[5] 8.18 km (calculated)[3] |
| 9.976 h[6] 19.2 h[7] | |
| 0.20 (assumed)[3] 0.2154±0.0284[5] 0.227±0.017[4] | |
| LS[8] · S[3] | |
| 12.22±0.25[8] · 12.8[1][3] · 13.2[5] | |
Orbit and classification
Niels orbits the Sun in the inner main-belt at a distance of 2.0â2.4 AU once every 3 years and 3 months (1,182 days). Its orbit has an eccentricity of 0.10 and an inclination of 1° with respect to the ecliptic.[1] First observed at Heidelberg in 1927, Niels' observation arc begins with its official discovery observation in 1935.[9]
Physical characteristics
Pan-STARRS classifies this stony asteroid as a LS-type, an intermediate to the rare L-type asteroids.[8]
Rotation period
A rotational lightcurve of Niels was obtained by astronomer Maurice Clark in December 2005. It gave it a rotation period of 9.976 hours with a brightness variation of 0.15 magnitude (U=1). In November 2008, photometric observations by amateur astronomer Pierre Antonini gave another period of 19.2 hours with an amplitude of 0.01 (U=1-). As of 2017, a secure period for Niels has not yet been obtained.
Diameter and albedo
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Niels measures 6.394 kilometers in diameter, and its surface has an albedo of 0.227,[4] superseding a preliminary result that gave a slightly larger diameter and lower albedo.[5] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.18 kilometers based on an absolute magnitude of 12.8.[3]
Naming
The minor planet was named by the discoverer after his grandson, Niels. Reinmuth also named 1719 Jens after one of his grandsons.[2] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3933).[10]
