Discovered by N. Sato Discovered 21 December 1997 Discoverer Naoto Satō Discovery site Chichibu Observatory | Discovery date 21 December 1997 Absolute magnitude 13.7 Asteroid group Asteroid belt | |
Alternative names 1997 YR2 · 1989 TM91999 CS56 Similar 135 Hertha, 142 Polana, 9922 Catcheller | ||
31179 Gongju, provisional designation 1997 YR2, is a stony asteroid from the inner regions of the asteroid belt, about 5 kilometers in diameter. It was discovered by Japanese amateur astronomer Naoto Sato at Chichibu Observatory near Tokyo, central Japan, on 21 December 1997.
The S-type asteroid is a member of the stony subgroup of the Nysa family, one of the smaller families in the main-belt, named after its namesake, 44 Nysa. The body orbits the Sun at a distance of 2.0–2.9 AU once every 3 years and 10 months (1,395 days). Its orbit shows an eccentricity of 0.19 and is tilted by 3 degrees to the plane of the ecliptic. In 2012, a light-curve analysis at the Shadowbox Observatory in Carmel, Indiana, rendered a rotation period of 7000482900000000000♠4.829±0.001 hours with an estimated amplitude of 0.80 in magnitude. It has an albedo of 0.35, according to the survey carried out by the Wide-field Infrared Survey Explorer with its NEOWISE mission, while the Collaborative Asteroid Lightcurve Link assumes a somewhat lower albedo of 0.21, a typical value for stony asteroids.
The minor planet was named after the South Korean city of Gongju, located in Chungcheongnam-do Province. It has a population of approximately 120,000 and was the capital of Baekje dynasty in the 5th century AD and the seat of the provincial government until 1932.