| Discovery[1] | |
|---|---|
| Discovered by | P. Wild |
| Discovery site | Zimmerwald Obs. |
| Discovery date | 2 September 1973 |
| Designations | |
| (2005) Hencke | |
Named after | Karl Ludwig Hencke (German astronomer)[2] |
| 1973 RA | |
| main-belt · Eunomia[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 43.26 yr (15,802 days) |
| Aphelion | 3.0590AU |
| Perihelion | 2.1826 AU |
| 2.6208 AU | |
| Eccentricity | 0.1672 |
| 4.24yr (1,550 days) | |
| 91.087° | |
| 0° 13m 56.28s / day | |
| Inclination | 12.220° |
| 291.09° | |
| 110.87° | |
| Physical characteristics | |
| Dimensions | 9.369±0.174 km[4][5] 10.53 km(calculated)[3] |
| 10.186±0.006h[6] | |
| 0.21(assumed)[3] 0.265±0.023[4][5] | |
| S[3] | |
| 12.2[1][3][4] · 12.40±0.32[7] | |
2005 Hencke, provisional designation1973 RA, is a stony Eunomiaasteroid from the middle region of theasteroid belt, approximately 10 kilometers in diameter. It was discovered by Swiss astronomerPaul Wild atZimmerwald Observatory near Bern, Switzerland, on 2 September 1973.[8] The asteroid was named after German amateur astronomerKarl Ludwig Hencke.[2]
The asteroid is a member of theEunomia family, a large group ofS-type asteroids and the most prominent family in the intermediate main-belt. It orbits the Sun in thecentral main-belt at a distance of 2.2–3.1 AU once every 4 years and 3 months (1,550 days). Its orbit has aneccentricity of 0.17 and aninclination of 12° with respect to theecliptic.[1] As noprecoveries were taken, the asteroid'sobservation arc begins with its discovery in 1973.[8]
In October 2007, a rotationallightcurve was obtained for this asteroid from photometric observations taken by U.S. astronomer James W. Brinsfield at the Via Capote Observatory in Thousand Oaks, California (G69). The lightcurve gave arotation period of10.186±0.006 hours with a brightness amplitude of 0.08 inmagnitude (U=2).[3]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer, the asteroid measures 9.4 kilometers in diameter and its surface has analbedo of 0.27,[4] while theCollaborative Asteroid Lightcurve Link assumes an albedo of 0.21, derived from the family's largest member and namesake,15 Eunomia, and calculates a diameter of 10.5 kilometers.[3]
Thisminor planet was named in honor of German amateur astronomerKarl Ludwig Hencke (1793–1866), apostmaster by profession, who discovered the main-belt asteroids5 Astraea and6 Hebe in 1845 and 1847, respectively.[2] The officialnaming citation was published by theMinor Planet Center on 15 October 1977 (M.P.C. 4238).[9]
