2111 Tselina
2111 Tselina ("prov. designation": ) is a stony Eos asteroid from the outer regions of the asteroid belt. It was discovered on 13 June 1969, by Soviet astronomer Tamara Smirnova at Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula. The S-type asteroid has a rotation period of 6.6 hours and measures approximately in diameter. It was later named after the Soviet Virgin Lands Campaign. Orbit and classification. "Tselina" is a member of the Eos family (), the largest asteroid family in the outer main belt consisting of nearly 10,000 asteroids. It orbits the Sun at a distance of  2.7–3.3 AU once every 5 years and 3 months (1,914 days). Its orbit has an eccentricity of 0.10 and an inclination of 11° with respect to the ecliptic. In 1929, "Tselina" was first observed as and by the German and Belgian observatories at Hamburg and Uccle, respectively. The body's observation arc begins at the discovering observatory in 1968, or one year prior to its official discovery. Naming. This minor planet was named after the tselina lands to commemorate the 25th anniversary of the Soviet Virgin Lands Campaign. The campaign was launched by Nikita Khrushchev in 1953, with the  intention to significantly increase the agricultural production in the USSR. The word "tselina" (or tseliny) means "virgin soil". The official naming citation was published by the Minor Planet Center on 1 April 1980 (). Physical characteristics. In the Tholen classification, "Tselina" is a common, stony S-type asteroid. Rotation period. In September 2001, a rotational lightcurve of "Tselina" was obtained from photometric observations by French amateur astronomer Laurent Bernasconi. Lightcurve analysis gave a well-defined rotation period of hours with a brightness variation of 0.17 magnitude (). In September 2012, observations by astronomers at the Palomar Transient Factory, California, gave a concurring  period of hours with an amplitude of 0.29 magnitude (). Diameter and albedo. 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, "Tselina" measures between 22.773 and 33.02 kilometers in diameter and its surface has an albedo between 0.13 and 0.226. The "Collaborative Asteroid Lightcurve Link" agrees with the results obtained by IRAS, that is, an albedo of 0.1938 and a diameter of 24.54 kilometers with an absolute magnitude of 10.45.