1764 Cogshall

1764 Cogshall, provisional designation, is a carbonaceous Themistian asteroid from the outer regions of the asteroid belt, approximately 26 kilometers in diameter. It was discovered on 7 November 1953 by astronomers of the Indiana Asteroid Program at Goethe Link Observatory in Indiana, United States. The asteroid was named after Wilbur Cogshall, professor of astronomy at Indiana University.

Orbit and classification
Cogshall is a Themistian asteroid that belongs to the Themis family (602), a very large family of carbonaceous asteroids named after 24 Themis. It orbits the Sun in the outer main belt at a distance of 2.7–3.5 AU once every 5 years and 5 months (1,987 days). Its orbit has an eccentricity of 0.12 and an inclination of 2° concerning to the ecliptic.

The asteroid was first identified as at Johannesburg Observatory in June 1935. The body's observation arc begins with its identification as at Turku Observatory in February 1939, more than 14 years before its official discovery observation at Goethe Link.

Rotation period
In May 2005, French amateur astronomer Pierre Antonini obtained a rotational lightcurve of Cogshall from photometric observations. Lightcurve analysis gave a well-defined rotation period of 3.62417 hours with a brightness variation of 0.21 magnitude (U=3).

Observations at the Palomar Transient Factory in 2012 gave a concurring period of 3.624 and 3.630 hours with an amplitude of 0.22 and 0.20 magnitude in the R- and S-band, respectively (U=2/2).

Diameter and albedo
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Cogshall measures between 25.14 and 29.671 kilometers in diameter, and its surface has an albedo between 0.0606 and 0.109.

The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0712 and a diameter of 26.13 kilometers based on an absolute magnitude of 11.4.

Naming
This minor planet was named after American astronomer Wilbur A. Cogshall, a professor of astronomy at Indiana University and director of the Kirkwood Observatory for more than four decades (1900–1944). His research included visual binary stars and the photography of solar eclipses. The name was proposed by Frank K. Edmondson, who initiated the Indiana Asteroid Program. The Minor Planet Center published the official on 20 February 1971 (M.P.C. 3143).