Discovered by Y. Väisälä MPC designation 1447 Utra Minor planet category main-belt · (middle) Absolute magnitude 11.3 Discoverer Yrjö Väisälä Asteroid group Asteroid belt | Discovery date 26 January 1938 Named after Utra (Finnish town) Discovered 26 January 1938 Orbits Sun Discovery site Iso-Heikkilä Observatory | |
Alternative names 1938 BB · 1936 SB1951 KO · A918 FA People also search for 1448 Lindbladia, 1446 Sillanpää | ||
1447 Utra, provisional designation 1938 BB, is a stony asteroid and slow rotator from the middle region of the asteroid belt, approximately 12 kilometers in diameter. It was discovered on 26 January 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.
Utra is a S-type asteroid. It orbits the Sun at a distance of 2.4–2.6 AU once every 4.04 years (1,474 days). Its orbit has an eccentricity of 0.04 and an inclination of 5° with respect to the ecliptic. Utra was first identified as A918 FA at Heidelberg Observatory in 1918. However, the body's observation arc begins with its official discovery observation at Turku.
In March 2011, a rotational light-curve of Utra was obtained from photometric observations by astronomer Luis E. Martinez. Light-curve analysis gave a long rotation period of 257 hours with a brightness variation of 0.63 magnitude (U=2). This slow rotator is also a suspected tumbler (T0).
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Utra measures between 11.83 and 13.26 kilometers in diameter, and its surface has an albedo between 0.303 and 0.381. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 13.58 kilometers based on an absolute magnitude of 11.7.
This minor planet was named for Utra, a northeastern Finnish town and birthplace of the discoverer. Naming citation was published before November 1977 (M.P.C. 2277).