Discovered by K. Reinmuth MPC designation 1628 Strobel Discovered 11 September 1923 Orbits Sun Asteroid group Asteroid belt | Discovery date 11 September 1923 Minor planet category main-belt · (outer) Absolute magnitude 10.02 Discoverer Karl Wilhelm Reinmuth | |
Named after Willi Strobel (astronomer) Alternative names 1923 OG · 1926 GY1947 GC · 1949 QA21952 DV2 · 1957 CA1960 WH Discovery site Landessternwarte Heidelberg-Königstuhl Similar Asteroid belt, Sun, 1862 Apollo, 1419 Danzig, 1056 Azalea | ||
1628 Strobel, provisional designation 1923 OG, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 55 kilometers in diameter. It was discovered on 11 September 1923, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany.
Strobel is a carbonaceous C-type asteroid, classified by WISE and Pan-STARRS as a P and X-type, respectively. It the orbits the Sun at a distance of 2.8–3.2 AU once every 5 years and 3 months (1,909 days). Its orbit has an eccentricity of 0.07 and an inclination of 19° with respect to the ecliptic. Strobel's observation arc begins two nights after its official discovery observation at Heidelberg in 1923.
American astronomer Richard P. Binzel obtained the first roational light-curve of Strobel in May 1984. It gave a rotation period of 11.80 hours with a brightness amplitude of 0.22 magnitude (U=2). In May 2005, photometric observations by French amateur astronomer Laurent Bernasconi gave a shorter period of 9.52 hours and a brightness change of 0.20 magnitude (U=2).
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, Strobel measures between 51.15 and 59.35 kilometers in diameter, and its surface has an albedo between 0.047 and 0.06. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0504 and a diameter of 57.06 kilometers based on an absolute magnitude of 10.08.
This minor planet was named in honor of Willi Strobel (1909–1988), staff member at Astronomisches Rechen-Institut (ARI) since 1938, and author of the 1963-edition of Identifizierungsnachweis der Kleinen Planeten (Minor planet identifications, published by ARI). Naming citation was published before November 1977 (M.P.C. 3931).