The
Themis or
Themistian asteroid family is a
Hirayama family (having similar
orbital elements) of asteroids found in the outer portion of the
asteroid belt, between the orbits of Mars and Jupiter. At a mean distance of 3.13
AU from the
Sun, it is one of the more populous
asteroid families. It consists of a well-defined core of larger asteroids and a surrounding region of smaller ones. This core group includes (and is named after) the asteroid
24 Themis, discovered on April 5, 1853 by Italian astronomer
Annibale de Gasparis.