11133 Kumotori

11133 Kumotori is a background asteroid from the central regions of the asteroid belt, approximately in diameter. It was discovered on 2 December 1996, by Japanese amateur astronomer Takao Kobayashi at his Ōizumi Observatory. The asteroid was named after Mount Kumotori near Tokyo. It has a rotation period of 4.6 hours.

Orbit and classification

Kumotori is a non-family asteroid from the main belt's background population. It orbits the Sun in the central main-belt at a distance of 2.6–2.9 AU once every 4 years and 8 months. Its orbit has an eccentricity of 0.06 and an inclination of 11° with respect to the ecliptic. The asteroid was first observed at Palomar Observatory in March 1989. The body's observation arc begins with its official discovery observation at Oizumi.

Kumotori has been characterized as a rare L-type asteroid by Pan-STARRS survey. It is also assumed to be a carbonaceous C-type asteroid.

In April 2012, a rotational lightcurve of Kumotori was obtained from photometric observations in the R-band by astronomers at the Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of 4.634 hours with a brightness amplitude of 0.33 magnitude.

The Collaborative Asteroid Lightcurve Link assumes an albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 8.96 kilometers based on an absolute magnitude of 13.97.

This minor planet was named after Mount Kumotori. With an altitude of, it is the highest peak in the Tokyo metropolitan area, located at the boundary between Tokyo and Saitama and considered to be one of the 100 most celebrated mountains of Japan. The official naming citation was published by the Minor Planet Center on 9 November 2003.