Discovered by T. Fujii
K. Watanabe MPC designation 5357 Sekiguchi Discovered 2 March 1992 Discovery site Kitami Observatory | Discovery date 2 March 1992 Minor planet category main-belt · (outer) Absolute magnitude 10.9 Asteroid group Asteroid belt | |
Named after Tomohiko Sekiguch
(astronomer) Alternative names 1992 EL · 1969 TB4
1971 BE3 · 1981 BH
1990 VJ4 · 1990 WU13 Discoverers Kazuro Watanabe, Tetsuya Fujii People also search for 5692 Shirao, 4971 Hoshinohiroba | ||
5357 Sekiguchi, provisional designation 1992 EL, is an asteroid from the outer region of the asteroid belt, approximately 15 kilometers in diameter. It was discovered on 2 March 1992, by Japanese amateur astronomers Tetsuya Fujii and Kazuro Watanabe at the Kitami Observatory in eastern Hokkaidō, Japan.
The asteroid orbits the Sun at a distance of 2.7–3.3 AU once every 5 years and 2 months (1,887 days). Its orbit has an eccentricity of 0.10 and an inclination of 9° with respect to the ecliptic. The first precovery was obtained at Goethe Link Observatory in 1950, extending the asteroid's observation arc by 42 years prior to its discovery.
A rotational light-curve of this asteroid was obtained by French astronomers René Roy and Laurent Bernasconi from photometric observations made in October 2005. It showed a rotation period of 7000541000000000000♠5.41±0.01 hours with a brightness variation of 0.72 in magnitude (U=3). In October 2010 and November 2011, two more light-curves were obtained at the U.S. Palomar Transient Factory, rendering a period of 5.4048 and 5.4100 hours with an amplitude of 0.58 and 0.27 in magnitude, respectively (U=2/2).
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its NEOWISE mission, the asteroid measures between 13.9 and 15.2 kilometers in diameter. However, the Collaborative Asteroid Lightcurve Link (CALL) calculates a much larger diameter of 25.4 kilometers. This is due to strongly divergent albedos, as the lower the reflectivity (albedo), the larger a body's diameter. While CALL assumes the body's surface to be of a carbonaceous composition, and classifies it as a dark C-type asteroid with a correspondingly low albedo of 0.057, the space-based surveys find higher albedos of 0.19, 0.33 and 0.38, respectively.
The minor planet was named in honor of Japanese astronomer Tomohiko Sekiguch (b. 1970), associate professor at Hokkaido University. From 1998 to 2001, he had been observing minor planets at the European Southern Observatory. Naming citation was published on 6 April 2012 (M.P.C. 79102).