Discovered by N. Chernykh MPC designation 4391 Balodis Discovered 21 August 1977 Orbits Sun Asteroid group Asteroid belt | Discovery date 21 August 1977 Minor planet category main-belt · Erigone Absolute magnitude 13.5 Discoverer Nikolai Chernykh | |
Named after Jānis Balodis (geodesist) Alternative names 1977 QW2 · 1977 RR2
1980 GZ Discovery site Crimean Astrophysical Observatory | ||
4391 Balodis, provisional designation 1977 QW2, is a dark and rare Erigone asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered by Soviet–Russian astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula, on 21 August 1977.
The C-type asteroid orbits the Sun at a distance of 1.9–2.9 AU once every 3 years and 8 months (1,350 days). Its orbit has an eccentricity of 0.21 and an inclination of 5° with respect to the ecliptic. Based on its orbital elements, the Collaborative Asteroid Lightcurve Link (CALL) classifies the asteroid as a member of the Erigone family, which is named after its largest member and namesake, 163 Erigone, also a dark body of carbonaceous composition.
According to observations by NASA's space-based Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid measures 3.4 kilometers in diameter, and its surface has an exceptionally high albedo of 0.40. However, the CALL assumes a much lower albedo of 0.06, a typical value for a carbonaceous asteroid, and calculates a diameter of 8.4 kilometers, as the lower the albedo (reflectivity) the larger the body's diameter at a constant absolute magnitude (brightness).
A rotational light-curve was obtained by Italian astronomer Albino Carbognani from photometric observations taken in July 2010, at the Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) in Italy. It showed rotation period of 7000344800000000000♠3.448±0.001 hours with a brightness amplitude of 0.29 in magnitude (U=2).
The minor planet was named after Latvian cosmic geodesist Jānis Balodis, head of the Astronomical Observatory at University of Latvia. His research includes astrometry, observations of artificial satellites using laser, as well as computational methods for astrometric interpretations of photographic plates. The Crimean minor planet service has used his algorithms for a long time. (The honored astronomer should not to be confused with Soviet army General Jānis Balodis.) Naming citation was published on 12 September 1992 (M.P.C. 20837).