1905 Ambartsumian

1905 Ambartsumian, provisional designation, is an asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 14 May 1972, by Russian astronomer Tamara Smirnova at the Crimean Astrophysical Observatory, Nauchnyj, on the Crimean peninsula. The asteroid was named after theoretical astrophysicist Victor Ambartsumian.

Orbit and classification
Ambartsumian orbits the Sun in the inner main-belt at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,211 days). Its orbit has an eccentricity of 0.16 and an inclination of 3° with respect to the ecliptic. It was first identified as at Simeiz Observatory in 1932, extending the body's observation arc by 40 years prior to its official discovery observation.

Physical characteristics
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Ambartsumian measures 8.0 kilometers in diameter and its surface has an albedo of 0.23. When using a generic diameter-to-magnitude conversion, it has a diameter of 7–17 kilometers, based on an absolute magnitude of 12.8 and an albedo in the range of 0.05–0.25, which accounts for both the brighter stony as well as for the darker carbonaceous spectral types. As of 2017, Ambartsumian's composition, rotation period and shape remain unknown.

Naming
This minor planet was named after Soviet–Armenian theoretical astrophysicist Victor Ambartsumian (1908–1996), founder of the Soviet School for Astrophysics, president of the Academy of Sciences of the Armenian SSR, director of the Byurakan Observatory, and president of the IAU (1961–1964). The official was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3937).