Discovered by K. Reinmuth Orbits Sun Discoverer Karl Wilhelm Reinmuth | Discovery date 6 October 1931 Discovered 6 October 1931 | |
Alternative names 1931 TG · 1930 MN1931 TA1 · 1953 FCA907 VD · A909 BDA917 XC · A917 YA Discovery site Landessternwarte Heidelberg-Königstuhl Similar 167 Urda, 277 Elvira, Asteroid belt, 311 Claudia, 360 Carlova | ||
1223 Neckar, provisional designation 1931 TG, is a stony Koronian asteroid from the outer region of the asteroid belt, approximately 25 kilometers in diameter. It was discovered on 6 October 1931, by German astronomer Karl Reinmuth at Heidelberg Observatory in southwest Germany, and named for the local river Neckar. Five nights later, it was independently discovered by Fernand Rigaux at Uccle in Belgium.
Description
Neckar is a S-type asteroid and member of the Koronis family, which is thought to have been formed at least two billion years ago in a catastrophic collision between two larger bodies. It orbits the Sun at a distance of 2.7–3.0 AU once every 4 years and 10 months (1,777 days). Its orbit has an eccentricity of 0.06 and an inclination of 3° with respect to the ecliptic. It was first identified as A907 VD at the discovering observatory in Heidelberg in 1907, extending the body's observation arc by 24 years prior to its official discovery observation.
Best rated rotational light-curve of Neckar gave a rotation period of 7.763 and 7.81 hours with a brightness variation of 0.18 and 0.45 magnitude, respectively (U=3/3). Photometric observations taken by Richard Binzel and Ed Tedesco in the 1970s and 1980s, however, gave a longer period and are now considered incorrect (U=0/0). Lightcurves with a period of 7.80 and 7.8273 hours (Δ0.21/0.28 mag) were also obtained at the Palomar Transient Factory in 2010 and 2014, respectively (U=2/2). Neckar's spin axis has been determined several times. Best rated result from a group lead by Polish astronomers gave a pole of (70.0°, 45.0°) in ecliptic coordinates.
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Neckar measures between 22.783 and 26.07 kilometers in diameter, and its surface has an albedo between 0.146 and 0.201. The Collaborative Asteroid Lightcurve Link adopts an albedo of 0.123 obtained by Morrison in the 1970s, and derives a diameter of 27.96 kilometers using an absolute magnitude of 10.66.
This minor planet was named after the river Neckar, running through the southwestern parts of Germany and in particular through the city of Heidelberg, location of the discovering observatory. The river origins in the Black Forrest and flows into the Rhine river. Naming citation was first mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 113).