1990 Pilcher
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1990 Pilcher, provisional designation Template:Mp, is a stony background asteroid from the Florian region of the inner asteroid belt, approximately Script error: No such module "convert". in diameter. It was discovered on 9 March 1956, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in Heidelberg, Germany. In 1982, it was named by the MPC for American physicist and photometrist Frederick Pilcher.[1] The S-type asteroid has a short rotation period of 2.8 hours.[2]
Orbit and classification
Pilcher is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method (HCM) to its proper orbital elements (Nesvorný, Milani and Knežević).[3][4] In a previous HCM-analysis (Zappalà) and based on osculating Keplerian orbital elements, the asteroid has also been classified as a member of the Flora family (402Script error: No such module "Check for unknown parameters".), a giant asteroid family and the largest family of stony asteroids in the main-belt.[2][5]
It orbits the Sun in the Florian region of the inner asteroid belt at a distance of 2.1–2.3 AU once every 3 years and 3 months (1,171 days; semi-major axis of 2.17 AU). Its orbit has an eccentricity of 0.05 and an inclination of 3° with respect to the ecliptic.[6]
The asteroid was first observed as Template:Mp at Nice Observatory in May 1937. The body's observation arc begins with a precovery taken at Palomar Observatory in June 1950, or six years prior to its official discovery observation at Heidelberg.[1]
Physical characteristics
In the Tholen classification, Pilcher is a common, stony S-type asteroid.[6]
Rotation period
In March 2017, a first rotational lightcurve of Pilcher was obtained from photometric observations at the Flarestar Observatory on the island of Malta. Lightcurve analysis gave a short rotation period of 2.842 hours with a brightness amplitude of 0.10 magnitude, indicative for a rather spherical shape (U=2+Script error: No such module "Check for unknown parameters".).[7]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Pilcher measures between 6.754 and 7.273 kilometers in diameter and its surface has an albedo between 0.1864 and 0.215.[8][9]
The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the Flora family's parent body and namesake – and calculates a diameter of 6.39 kilometers based on an absolute magnitude of 13.14.[2]
Naming
This minor planet was named after American astronomer Frederick Pilcher, a retired professor of Physics at Illinois College and prolific lightcurve photometrist at his Organ Mesa Observatory Template:Obscode in New Mexico.[1] The official naming citation was published by the Minor Planet Center on 8 April 1982 (M.P.C. 6833Script error: No such module "Check for unknown parameters".).[10]
References
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External links
- Minor Planet Lightcurve Data (Frederick Pilcher), Astronomical Society of Las Cruces (ASLC)
- Asteroid Lightcurve Database (LCDB), query form (info Script error: No such module "webarchive".)
- Dictionary of Minor Planet Names, Google books
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- Template:AstDys
- Template:PAGENAMEBASE at the JPL Small-Body DatabaseTemplate:EditAtWikidata
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