Discovered by O. Oikawa
K. Kubokawa Named after Atami (Japanese city) Minor planet category Mars-crosser Discovered 1 December 1929 Asteroid group Mars-crosser asteroid | Discovery date 1 December 1929 Alternative names 1929 XE Observation arc 87.10 yr (31,814 days) Orbits Sun MPC designation 1139 | |
Discoverers Kazuo Kubokawa, Okuro Oikawa Discovery site Tokyo Astronomical Observatory, Tokyo Astronomical Observatory (before 1938) People also search for 1131 Porzia, 1089 Tama, 1138 Attica | ||
1139 Atami, provisional designation 1929 XE, is a binary asteroid and Mars-crosser, approximately 9 kilometers in diameter. It was discovered on 1 December 1929, by Japanese astronomers Okuro Oikawa and Kazuo Kubokawa at the Tokyo Astronomical Observatory () near Tokyo.
The stony S-type asteroid orbits the Sun at a distance of 1.5–2.4 AU once every 2 years and 9 months (993 days). Its orbit has an eccentricity of 0.26 and an inclination of 13° with respect to the ecliptic.
In 2005, two rotational light-curves obtained at the U.S. Antelope Hills Observatory in New Mexico and by a collaboration of several European astronomers gave a rotation period of 7001275600000000000♠27.56±0.01 and 7001274460000000000♠27.446±0.001 hours with a brightness variation of 0.45 and 0.40 in magnitude, respectively (U=3/3).
The minor planet was named after Atami, a Japanese city and harbor near Tokyo, Japan. Naming citation was first mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 106).
Binary system
Photometric and Arecibo echo spectra observations in 2005 confirmed a 5 kilometer satellite orbiting at least 15 kilometers from its primary. Due to the similar size of the primary and secondary the Minor Planet Center lists this as a binary companion.