Neckar was discovered on 6 October 1931, by German astronomer
Karl Reinmuth at
Heidelberg Observatory in southwest Germany.[1] Five nights later, it was independently discovered by
Fernand Rigaux at
Uccle in Belgium.[2] The
Minor Planet Center only acknowledges the first discoverer.[1] The asteroid was observed as A907 VD at Heidelberg in November 1907, extending its
observation arc by 24 years prior to its official discovery observation.[1]
Orbit and classification
Neckar is a core member of the
Koronis family (605),[5] a very large outer
asteroid family with nearly co-planar ecliptical orbits. The family, named after
158 Koronis, is thought to have been formed at least two billion years ago in a catastrophic collision between two larger bodies. It orbits the Sun in the
outer main-belt at a distance of 2.7–3.0
AU once every 4 years and 10 months (1,775 days;
semi-major axis of 2.87 AU). Its orbit has an
eccentricity of 0.06 and an
inclination of 3
° with respect to the
ecliptic.[3]
Two lightcurves in the R-band 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).[14][16]Neckar's spin axes has been determined several times. The best rated result, from a group led by Polish astronomers, gave two
poles at (70.0°, 45.0°) and (225.0°, 42.0°) in
ecliptic coordinates.[13]
Diameter and albedo
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.[8][9][10][11][12] The Collaborative Asteroid Lightcurve Link adopts an albedo of 0.123 obtained by Morrison in the 1970s,[18] and derives a diameter of 27.96 kilometers using an
absolute magnitude of 10.66.[4]
Naming
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).[2]
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abcWaszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35.
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