Discovered by P. Wild Minor planet category main-belt · Phocaea Discovered 6 February 1967 | Discovery date 6 February 1967 Alternative names 1967 CA · 1931 DL Observation arc 85.73 yr (31,313 days) Orbits Sun Asteroid group Asteroid belt | |
Similar Sun, 3552 Don Quixote, 81P/Wild | ||
1803 Zwicky, provisional designation 1967 CA, is a stony Phocaea asteroid from the inner regions of the asteroid belt, approximately 10 kilometers in diameter. It was discovered on 6 February 1967, by Swiss astronomer Paul Wild at Zimmerwald Observatory near Bern, Switzerland.
The S-type asteroid is a member of the Phocaea family, a smaller population of asteroids with similar orbital characteristics and named after their largest member, 25 Phocaea. Zwicky orbits the Sun at a distance of 1.8–2.9 AU once every 3 years and 7 months (1,315 days). Its orbit has an eccentricity of 0.25 and an inclination of 22° with respect to the ecliptic. It was first identified as 1931 DL at Lowell Observatory in 1931, extending the body's observation arc by 36 years prior to its official discovery observation.
In March 2003, a fragmentary light-curve of Zwicky was obtained from photometric observations by French amateur astronomer Laurent Bernasconi. It gave a rotation period of 27.1 hours with a brightness amplitude of 0.08 magnitude (U=1). As of 2017, no other rotational light-curves have been obtained.
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Zwicky measures between 9.2 and 10.2 kilometers in diameter, and its surface has an albedo between 0.25 and 0.34. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for Phocaea asteroids of 0.23, and calculates a diameter of 10.54 kilometers based on an absolute magnitude of 12.2.
The asteroid was named after Swiss astronomer Fritz Zwicky (1898–1974), who was a professor at Caltech and a pioneer in many fields, most notably in the study of galaxy clusters and supernovas, in high-energy astrophysics, and in developing jet propulsion for spacecraft and airplanes. He was the first to infer the existence of unseen matter and coined the term Dark matter. The lunar crater Zwicky is also named in his honour. Naming citation was published before November 1977 (M.P.C. 4156).