1428 Mombasa, provisional designation , is a dark asteroid from the middle region of the asteroid belt, approximately 56 kilometers in diameter.
It was discovered on 5 July 1937, by English-born South African astronomer Cyril Jackson at Johannesburg Observatory, South Africa, and later named after Mombasa, Kenya.
Mombasa orbits the Sun at a distance of 2.4âÂÂ3.2 AU once every 4 years and 9 months (1,720 days). Its orbit has an eccentricity of 0.14 and an inclination of 17ð with respect to the ecliptic. Mombasa was first identified as at Lowell Observatory, extending the body's observation arc by 4 years prior to its official discovery at Johannesburg.
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 (). Previous lightcurves were obtained by French amateur astronomer René Roy in February 2006 (17.6 hours, ÃÂ0.15 mag; ), as well as by Scot Hawkins and Richard Ditteon at Oakley Observatory in May 2007 (17.12 hours, ÃÂ0.25 mag; ).
On the SMASS taxonomic scheme, Mombasa is a , an intermediate between the carbonaceous C and X-type, while it is also described as a darker P-type asteroid. 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, and its surface has an albedo of 0.025 and 0.06. 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.
This minor planet was named after Mombasa, chief-port and second largest city of Kenya on the coast of East Africa. The official was published by the Minor Planet Center in April 1953 ().