| Discovery[1] | |
|---|---|
| Discovered by | T. Fujii K. Watanabe |
| Discovery site | Kitami Obs. |
| Discovery date | 3 December 1988 |
| Designations | |
| (5474) Gingasen | |
Named after | Gingasen (railroad track, Japan)[2] |
| 1988 XE1 · 1955 YK 1971 BO2 | |
| main-belt · Vestian[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 45.58 yr (16,649 days) |
| Aphelion | 2.5439AU |
| Perihelion | 2.2232 AU |
| 2.3836 AU | |
| Eccentricity | 0.0673 |
| 3.68yr (1,344 days) | |
| 219.47° | |
| 0° 16m 4.08s / day | |
| Inclination | 6.1443° |
| 246.97° | |
| 256.31° | |
| Knownsatellites | 1(suspected)[4][5] (orbital period of 3.1095h) |
| Physical characteristics | |
| Dimensions | 5.05±0.48 km[6] 6.68 km(derived)[3] |
| 2.91h(superseded)[7] 3.6242±0.0003 h[4][a] 3.6272±0.0015 h[8] 3.628±0.005 h[9] | |
| 0.20(assumed)[3] 0.480±0.109[6] | |
| S[3] | |
| 12.70±0.2(R)[4] · 12.79±0.10(R)[a] · 12.886±0.002(R)[8] · 12.90[6] · 13.1[1] · 13.14±0.35[10] · 13.28±0.112[3][11] | |
5474 Gingasen, provisional designation1988 XE1, is a Vestianasteroid and suspectedbinary system[4] from the inner regions of theasteroid belt, approximately 6 kilometers in diameter.
It was discovered on 3 December 1988, by Japanese amateur astronomersTetsuya Fujii andKazuro Watanabe atKitami Observatory, Japan.[12] It is named for the "Gingasen" railroad track in Japan.[2]
Gingasen is a stonyS-type asteroid and member of theVesta family. It orbits the Sun in theinner main-belt at a distance of 2.2–2.5 AU once every 3 years and 8 months (1,344 days). Its orbit has aneccentricity of 0.07 and aninclination of 6° with respect to theecliptic.[1] First identified as1955 YK at Alma-Ata (Tian Shan Observatory) in Kazakhstan,Gingasen's first used observation was taken in 1971, when it was identified as1971 BO2 atCerro El Roble Station in Chile, extending the body'sobservation arc by 17 years prior to its official discovery observation.[12]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Gingasen measures 5.05 kilometers in diameter, and its surface has a highalbedo of 0.480,[6] while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and derives a diameter of 6.68 kilometers with anabsolute magnitude of 13.28.[3]
Four rotationallightcurves ofGingasen were obtained byPetr Pravec,David Higgins and Pedro Sada in 2008, as well as from thePalomar Transient Factory in 2010. The lightcurves gave a well-definedrotation period of 3.624 to 3.628 hours with a brightness variation of 0.11–0.18 inmagnitude (U=3/3/3-/2),[4][8][9][a] superseding a previous result byLaurent Bernasconi (U=1-).[7]
During the photometric observations in 2008, the astronomers came across strong evidence thatGingasen is likely an asynchronousbinary asteroid with anasteroid moon orbiting it every 3.1095 hours. However, no mutualoccultation/eclipse events were observed.[4][5]
Thisminor planet was named after a railroad track in Hokkaido. Gingasen means "Milky Way". This 150-km public railroad connects the island's eastern cities. Each station along the line is named for a constellation.[12] The approved naming citation was published by theMinor Planet Center on 4 April 1996 (M.P.C. 26930).[13]
