5481 Kiuchi


5481 Kiuchi, provisional designation , is a bright binary Vestian asteroid from the inner regions of the asteroid belt, approximately in diameter. It was discovered on 15 February 1990, by Japanese astronomers Kin Endate and Kazuro Watanabe at Kitami Observatory in Hokkaidō, Japan, and named after their colleague Tsuruhiko Kiuchi. The V-type asteroid has a rotation period of 3.6 hours.

Family and orbit

Kiuchi is a bright core member of the Vesta family, one of the main-belt's largest families. It orbits the Sun in the inner main-belt at a distance of 2.2–2.5 AU once every 3 years and 7 months. Its orbit has an eccentricity of 0.06 and an inclination of 6° with respect to the ecliptic. It was first identified as at Crimea–Nauchnij in 1970, extending the body's observation arc by 20 years prior to its official discovery observation at Kitami.

Naming

This minor planet was named in honor of Japanese amateur astronomer and discoverer of comets, Tsuruhiko Kiuchi, who is known for the rediscovery of the periodic Perseid Comet Swift–Tuttle, a previously lost comet.

Binary asteroid

Satellite

In March 2008, a lightcurve of Kiuchi was obtained from photometric observations by astronomers Peter Kušnirák and Petr Pravec at Ondřejov Observatory in the Czech Republic, by Julian Oey at Leura Observatory, Australia, by Robert Stephens at Goat Mountain, California, by Mark Husárik at Skalnaté pleso Observatory, Slovakia, and by Judit Györgyey Ries at McDonald Observatory, Texas.
These photometric observations revealed, that Kiuchi is a synchronous binary asteroid with a minor-planet moon orbiting it every 20.90 hours based on mutual eclipsing and occultation events. The satellite's diameter is about a third of that of Kiuchi, which translates into 1.3 kilometers.

Primary

According to the surveys carried out by PanSTARRS, Kiuchi is a bright V-type asteroid. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.40 and calculates a diameter of 3.86 kilometers, using an absolute magnitude of 13.676 from Petr Pravec's revised WISE data.
Kiuchi itself has a rotation period of hours with a small brightness variation of 0.1 magnitude, indicating a nearly spheroidal shape. Photometric follow-up observations by Petr Pravec confirmed the results in 2013 and 2016, giving a period of 3.6198 and 3.6196 hours with an amplitude of 0.08 and 0.1 magnitude, and an orbital period for the satellite of 20.9 and 20.9062 hours, respectively.