It was discovered on 23 March 1992, by Japanese amateur astronomers Kin Endate and Kazuro Watanabe at Kitami Observatory, Hokkaidō, Japan.
It orbits the Sun in the central main-belt at a distance of 2.2–3.1 AU once every 4 years and 4 months (1,580 days).
[10] In June 2014, a rotational lightcurve of Shirao was obtained from photometric observations made by American astronomer Brian Warner at his Palmer Divide Observatory (716) in Colorado.
[3][8] According to the surveys carried out by NASA's Wide-field Infrared Survey Explorer and its subsequent NEOWISE mission, Shirao measures between 9.5 and 9.8 kilometers in diameter and its surface has an albedo of 0.22,[4][5][6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo of 0.21 – derived from 15 Eunomia, the largest member and namesake of this asteroid family – and calculates a diameter of 9.2 kilometers.
[3] This minor planet was named after Motomaro Shirao (born 1953), a Japanese geologist and astrophotographer, who is known for his photographs of volcanoes and lunar geological features.