Discovered by Y. Väisälä Alternative names 1938 UY · 1938 YH Discovered 22 October 1938 Orbits Sun Discovery site Iso-Heikkilä Observatory | Discovery date 22 October 1938 Minor planet category main-belt · (outer) Absolute magnitude 10 Discoverer Yrjö Väisälä Asteroid group Asteroid belt | |
People also search for 1519 Kajaani, 1548 Palomaa | ||
1520 Imatra, provisional designation 1938 UY, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 53.5 kilometers in diameter. It was discovered on 22 October 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.
Imatra is a C-type asteroid in the SMASS taxonomy. It orbits the Sun at a distance of 2.8–3.4 AU once every 5 years and 6 months (2,003 days). Its orbit has an eccentricity of 0.10 and an inclination of 15° with respect to the ecliptic. No precoveries and no prior identifications were made. Imatra's observation arc begins at Turku, 3 weeks after its official discovery observation.
In July 2008, American astronomer Brian D. Warner obtained a rotational light-curve of Imatra at his Palmer Divide Observatory in Colorado. It gave a rotation period of 18.635 hours with a brightness variation of 0.28 magnitude (U=3-), superseding a period of 5.23 hours from observations at Italian and French observatories in the 1990s (U=2). In September 2014, a photometric observations by French amateur astronomers Laurent Bernasconi, Romain Montaigut and Arnaud Leroy gave a period of 18.609 hours with an amplitude of 0.27 magnitude (U=2+).
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Imatra measures between 53.42 and 58.63 kilometers in diameter, and its surface has an albedo between 0.039 and 0.062. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0428 and a diameter of 53.41 kilometers using an absolute magnitude of 10.4.
This minor planet is named for the south-eastern Finnish town Imatra, located in South Karelia near the Russian border, about half way in between St Petersburg and Finland's capital Helsinki. Naming citation was published before November 1977 (M.P.C. 3929).