Discovered by T. Smirnova MPC designation 1857 Parchomenko Orbital period 1,227 days Absolute magnitude 12.3 Discoverer Tamara Smirnova | Discovery date 30 August 1971 Minor planet category main-belt · (inner) Discovered 30 August 1971 Orbits Sun Asteroid group Asteroid belt | |
Named after Praskoviya Parchomenko
(astronomer) Alternative names 1971 QS1 · 1931 XT
1941 WJ · 1974 OE1 Discovery site Crimean Astrophysical Observatory | ||
1857 Parchomenko, provisional designation 1971 QS1, is a stony asteroid and suspected binary from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 30 August 1971, by Russian astronomer Tamara Smirnova at Crimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula.
The S-type asteroid orbits the Sun at a distance of 1.9–2.5 AU once every 3 years and 4 months (1,228 days). Its orbit has an eccentricity of 0.13 and an inclination of 4° with respect to the ecliptic. First identified as 1931 XT at Lowell Observatory, the first used observation of Parchomenko was taken at Nice Observatory in 1939, extending the body's observation arc by 32 years prior to its official discovery observation.
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Parchomenko measures 7.99 and 9.84 kilometers in diameter, and its surface has an albedo of 0.295 and 0.333, respectively. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.5 kilometers, based on an absolute magnitude of 12.4.
In December 2005, a rotational light-curve of Parchomenko was obtained from a photometric observations by Robert D. Stephens, Brian D. Warner and Petr Pravec. It gave a well-defined rotation period of 3.1177 hours with a brightness variation of 0.22 magnitude (U=3). Three possible occultation events were observed, suggesting that Parchomenko might be a binary asteroid, having an asteroid moon as companion. However, no new findings have been made since. In October 2008, Italian amateur astronomer Silvano Casulli measured a similar period of 3.08 hours with an amplitude of 0.27 magnitude (U=3).
This minor planet was named in honor of astronomer Praskoviya Parchomenko (1886–1970), who observed and discovered the minor planets 1129 Neujmina and 1166 Sakuntala at the Crimean Simeiz Observatory during the 1930s and 1940s. Naming citation was published before November 1977 (M.P.C. 3826).