1428 Mombasa

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.

Orbit and classification
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. Mombasa was first identified as at Lowell Observatory, extending the body's observation arc by 4 years prior to its official discovery at Johannesburg.

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+). Previous lightcurves were obtained by French amateur astronomer René Roy in February 2006 (17.6 hours, Δ0.15 mag; U=2), as well as by Scot Hawkins and Richard Ditteon at Oakley Observatory in May 2007 (17.12 hours, Δ0.25 mag; U=2).

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. 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.

Naming
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 (M.P.C. 909).