7369 Gavrilin

7369 Gavrilin (provisional designation 1975 AN) is a stony asteroid from the inner asteroid belt, classified as both a member of the Phocaea family and a Mars-crosser. It follows an eccentric orbit, crossing the path of Mars at 1.66 AU, and takes about three years and eight months to circle the Sun at distances ranging from 1.6 to 3.1 AU. The asteroid measures roughly 5.5 kilometers across, making it one of the smaller sizable Mars-crossers (those between 5 and 15 kilometers in diameter).

Rotation period and satellite

It was discovered on 13 January 1975 by Russian astronomer Tamara Smirnova at the Crimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula. The first observation of the object had been made eleven days earlier at the Purple Mountain Observatory. The asteroid is an assumed S-type (stony) body, the most common spectral type in the inner belt, which aligns with the typical composition of the Phocaea family. Its rotation period is unusually long at 49.12 hours, as determined from photometric lightcurve observations in January 2008 by the BINAST group, including David Higgins at Hunters Hill Observatory and Petr Pravec at Ondřejov Observatory.

Those same observations revealed that 7369 Gavrilin is a synchronous binary system: it has a moon about 2.41 kilometers in diameter (at least 0.32 times the primary’s size), which orbits the primary in the same 49.12-hour period. The discovery of the satellite was announced in October 2008. Diameter estimates vary. Data from the NEOWISE mission give values of 4.91 and 5.49 kilometers with albedos of 0.27 and 0.28, while a 2017 WISE study of Mars-crossers reports a diameter of 5.51 kilometers despite a higher albedo of 0.305.

The Collaborative Asteroid Lightcurve Link assumes a standard stony albedo of 0.20 and calculates a diameter of 5.74 kilometers based on an absolute magnitude of 13.61, whereas Johnston’s Archive estimates the primary alone at 7.54 kilometers. The asteroid was numbered on 23 January 1997 (M.P.C. 28817) and named on 24 January 2000 (M.P.C. 38196) after the Russian composer Valery Gavrilin (1939–1999). The name was suggested by the Union of Concert Workers of Russia.