[6] Okamoto is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.
[7][6][8][9] Analysis of the best-rated lightcurve gave a well-defined rotation period of 2.8958 hours with a consolidated brightness amplitude between 0.11 and 0.15 magnitude (U=3).
[4] Based on an assumed albedo of 0.14, the Johnston's archive estimates a diameter of 6.69 and 6.89 kilometer for the primary and the combined system, respectively (see below).
[5] In 2006, photometric observations obtained by David Higgins (E14) at Canberra, Australia, Donald Pray at Carbuncle Hill Observatory (912), as well as Peter Kušnirák and Petr Pravec at Ondřejov Observatory revealed that Okamoto is a synchronous binary asteroid with a minor-planet moon orbiting it every 20.32 hours at an estimated average distance of 13 km.
[4][5] This minor planet was named after Japanese Entomologist and elementary-school teacher Hiroshi Okamoto (born 1915), who inspired the discoverer Tsutomu Seki with a love of the stars.