1428 Mombasa, provisional designation 1937 NO, is a dark
asteroid from the middle region of the
asteroid belt, approximately 56 kilometers in diameter.
Mombasa orbits the Sun at a distance of 2.4–3.2
AU once every 4 years and 9 months (1,720 days). Its orbit has an
eccentricity of 0.14 and an
inclination of 17
° with respect to the
ecliptic.[1]Mombasa was first identified as 1933 WO at
Lowell Observatory, extending the body's
observation arc by 4 years prior to its official discovery at Johannesburg.[14]
Physical characteristics
Rotation period
American astronomer
Robert Stephens obtained a rotational
lightcurve of Mombasa in June 2012. Light-curve analysis gave a
rotation period of 16.67 hours with a brightness variation of 0.16
magnitude (U=2+).[a] Previous lightcurves were obtained by French amateur astronomer
René Roy in February 2006 (17.6 hours, Δ0.15 mag; U=2),[12] as well as by Scot Hawkins and Richard Ditteon at
Oakley Observatory in May 2007 (17.12 hours, Δ0.25 mag; U=2).[11]
Spectral type, diameter and albedo
On the
SMASS taxonomic scheme, Mombasa is a
Xc-type, an intermediate between the carbonaceous
C and
X-type, while it is also described as a darker
P-type asteroid.[10] 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, Mombasa measures between 52.46 and 62.45 kilometers in diameter, ignoring a preliminary result of 127 km,[10] and its surface has an
albedo of 0.025 and 0.06.[3][4][5][6][8][9] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0415 and a diameter of 56.83 kilometers with an
absolute magnitude of 10.3.[7]