4786 Tatianina

Lore & Background

4786 Tatianina was discovered on 13 August 1985 by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula. It was named after Tatiana Aleksandrovna Somova, a nursery-school teacher in Saint Petersburg, Russia, and a friend of the discoverer. The asteroid was first observed as 1948 GA at the Algiers Observatory in April 1948, and its observation arc began at Nauchnij in May 1970 as 1970 KF, more than 15 years prior to its official discovery.

In terms of physical characteristics, Tatianina is classified as an Xc-subtype in the SMASS scheme, transitioning from X-type to carbonaceous C-type asteroids, and has also been characterized as a bright E-type by the Wide-field Infrared Survey Explorer (WISE). Its rotation period is 2.9227 hours based on a March 2003 lightcurve, with a brightness amplitude of 0.19 to 0.20 magnitude. The asteroid measures between 3.282 and 3.475 kilometers in diameter and has an exceptionally high albedo of 0.4763 to 0.514, as determined by the NEOWISE mission.

During photometric observations by Donald Pray, Petr Pravec and collaborators in March 2006, it was revealed that Tatianina is a synchronous binary asteroid with a minor-planet moon orbiting it every 21.67 hours at an estimated average distance of 6.6 km. The discovery was announced on 11 April 2006. The mutual occultation events suggest the satellite has an estimated diameter of 610±10 meters, or 19% the size of the primary.

Reader's Guide

The significance of 4786 Tatianina lies in its status as a synchronous binary asteroid, a relatively rare configuration where the moon's orbital period matches the primary's rotation. Discovered in March 2006 and announced the following month, the satellite was detected through photometric observations by Donald Pray, Petr Pravec and collaborators, who observed mutual occultation events. This binary system provides insights into the formation and evolution of small asteroid pairs in the inner main belt. The asteroid's exceptionally high albedo (0.4763 to 0.514) and classification as both Xc-subtype and E-type highlight its unusual surface composition. Its orbit in the background population of the inner asteroid belt, with a semi-major axis of 2.36 AU, eccentricity of 0.19, and inclination of 7°, places it among the non-family asteroids. The naming after Tatiana Aleksandrovna Somova, a nursery-school teacher, reflects the personal connection of the discoverer. The asteroid was numbered on 28 April 1991, and the naming citation was published on 5 March 1996.