Discovered by T. Fujii
K. Watanabe MPC designation 5474 Gingasen Discovered 3 December 1988 Asteroid family Vesta family Asteroid group Asteroid belt | Discovery date 3 December 1988 Minor planet category main-belt · Vestian Orbits Sun Discovery site Kitami Observatory | |
Named after Gingasen
(railroad track, Japan) Alternative names 1988 XE1 · 1955 YK
1971 BO2 Discoverers Kazuro Watanabe, Tetsuya Fujii People also search for 5481 Kiuchi, 5692 Shirao, Sun | ||
5474 Gingasen, provisional designation 1988 XE1, is a Vestian asteroid and suspected binary from the inner regions of the asteroid belt, approximately 6 kilometers in diameter. It was discovered on 3 December 1988, by Japanese amateur astronomers Tetsuya Fujii and Kazuro Watanabe at Kitami Observatory, Japan.
Gingasen is a stony S-type asteroid and member of the Vesta family. It orbits the Sun at a distance of 2.2–2.5 AU once every 3 years and 8 months (1,344 days). Its orbit has an eccentricity of 0.07 and an inclination of 6° with respect to the ecliptic. First identified as 1955 YK at Alma-Ata (Tian Shan Observatory) in Kazakhstan, Gingasen's first used observation was taken in 1971, when it was identified as 1971 BO2 at Cerro El Roble Station in Chile, extending the body's observation arc by 17 years prior to its official discovery observation.
Four rotational light-curves of Gingasen were obtained by Petr Pravec, David Higgins and Pedro Sada in 2008, as well as from the Palomar Transient Factory in 2010. The light-curves gave a well-defined rotation period of 3.624 to 3.628 hours with a brightness variation of 0.11–0.18 in magnitude (U=3/3/3-/2), superseding a previous result by Laurent Bernasconi (U=1-).
During the photometric observations in 2008, the astronomers came across strong evidence that Gingasen is likely an asynchronous binary asteroid with an asteroid moon orbiting it every 3.1095 hours. However, no mutual occultation/eclipse events were observed.
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Gingasen measures 5.05 kilometers in diameter, and its surface has a high albedo of 0.480, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and derives a diameter of 6.68 kilometers based on an absolute magnitude of 13.28.
The minor 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. Naming citation was published on 4 April 1996 (M.P.C. 26930).