1139 Atami is a Mars-crossing asteroid orbiting the Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

. It makes a revolution around the Sun once every 3 years. It completes one rotation once every 27 hours. It was discovered by Okuro Oikawa

Okuro Oikawa

was a Japanese astronomer.He discovered 8 asteroids.The asteroid 2667 Oikawa is named after him....

 and Kazuo Kubokawa

Kazuo Kubokawa

was a Japanese astronomer.He co-discovered the asteroid 1139 Atami.During the Japanese period in Taiwan, he was president of the Astronomical Association, Taiwan Branch beginning in 1938. He began to build "New High Mountain Observatory" in 1942, but died the following year.-External links:*...

 on December 1, 1929. It is named after a harbor near Tokyo

Tokyo

, ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...

, Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

. Its provisional designation was 1929 XE.

Binary system

Photometric and Arecibo echo spectra

Arecibo Observatory

The Arecibo Observatory is a radio telescope near the city of Arecibo in Puerto Rico. It is operated by SRI International under cooperative agreement with the National Science Foundation...

 observations in 2005 confirmed a 5 km (3 mi) satellite orbiting at least 15 km (9 mi) from the primary. Due to the similar size of the primary and secondary the Minor Planet Center

Minor Planet Center

The Minor Planet Center operates at the Smithsonian Astrophysical Observatory , which is part of the Center for Astrophysics along with the Harvard College Observatory ....

 lists this as a binary companion

Binary system (astronomy)

A binary system is an astronomical term referring to two objects in space which are so close that their gravitational interaction causes them to orbit about a common center of mass. Some definitions A binary system is an astronomical term referring to two objects in space (usually stars, but also...

.

External links

• Orbital simulation from JPL (Java) / Ephemeris