| Discovery [1] | |
|---|---|
| Discovered by | K. Endate K. Watanabe |
| Discovery site | Kitami Obs. |
| Discovery date | 25 November 1987 |
| Designations | |
| (4607) Seilandfarm | |
Named after | Seilandfarm (Japanesefarm)[2] |
| 1987 WR · 1951 CK1 1975 EO4 | |
| main-belt · (inner) [3] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 42.23 yr (15,424 days) |
| Aphelion | 2.3083AU |
| Perihelion | 2.2194 AU |
| 2.2638 AU | |
| Eccentricity | 0.0196 |
| 3.41yr (1,244 days) | |
| 225.75° | |
| 0° 17m 21.84s / day | |
| Inclination | 2.2522° |
| 250.50° | |
| 219.80° | |
| Knownsatellites | 1 [a][4] |
| Physical characteristics | |
| Dimensions | 6.33±0.27 km[5] 7.13 km(calculated)[3] 7.389±0.115 km[6] 7.482±0.136[7] |
| 3.9681±0.0002h[b] 3.9683±0.0001 h[b][4] | |
| 0.178±0.032[7] 0.20(assumed)[3] 0.2239±0.0142[6] 0.279±0.035[5] | |
| SMASS =L [1] · L [3] | |
| 12.89±0.34[8] · 12.9[6] · 13.00[5] · 13.1[1] · 13.2[3] | |
4607 Seilandfarm, provisional designation1987 WR, is a rare-typebinary[a]asteroid from the inner regions of theasteroid belt, approximately 7 kilometers in diameter.
It was discovered on 25 November 1987, by Japanese amateur astronomersKin Endate andKazuro Watanabe atKitami Observatory on the Japanese island of Hokkaidō.[9] It was named for a dairy and cattle farm with the same name, located near the Japanese city of Kitami.[2]
Seilandfarm orbits the Sun in theinner main-belt at a distance of 2.2–2.3 AU once every 3 years and 5 months (1,244 days). Its orbit has aneccentricity of 0.02 and aninclination of 2° with respect to theecliptic.[1]
In February 1951, the asteroid was first identified as1951 CK1 at Abastuman Observatory (119) in Georgia. The body'sobservation arc begins with its official discovery observation at Kitami.[9]
On theSMASS taxonomic scheme,Seilandfarm is classified as a rare and reddishL-type asteroid.[1]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer with itsNEOWISE mission,Seilandfarm measures between 6.3 and 7.5 and kilometers in diameter, and its surface has a correspondingalbedo between 0.178 and 0.279,[5][6][7] while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 7.1 kilometers, in agreement with the results obtained by the space-based observations.[3]
In February 2009 and September 2014, three rotationallightcurves were obtained from photometric observations by astronomersDonald P. Pray andPetr Pravec at the U.S. Carbuncle and the Czech Ondřejov Observatory, respectively. The lightcurves rendered a well-definedrotation period of3.9681 and3.9683 hours with a corresponding brightness variation of 0.15 and 0.17magnitude, indicating that the asteroid's shape is nearly spheroidal (U=3/3/3).[b][4]
During the photometric observations in February 2009, it was discovered thatSeilandfarm is in fact abinary system. Itsminor-planet moon has an orbital period of 31.6 hours. Based on mutual eclipse/occultation events, the satellite is thought to be at least 29% the size ofSeilandfarm,[a] which translates into a diameter of approximately 2 kilometers or more.
Thisminor planet was named forSeilandfarm, a 50-hectare dairy and cattle farm, located in a hilly terrain, near the Japanese city of Kitami and not far from the observatory where this minor planet was discovered(also see3785 Kitami). The farm was established by Akio Seino in 1942, and is now operated by four members of the Seino family.[2] The approved naming citation was published by theMinor Planet Center on 14 July 1992 (M.P.C. 20521).[10]
