2311 El Leoncito, provisional designation , is a dark and reddish
asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
from the outer region of the
asteroid belt
The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...
, approximately 53 kilometers in diameter. The asteroid was discovered by astronomers at
Félix Aguilar Observatory
Félix Aguilar Observatory ( ; OAFA) is an astronomical observatory established in 1953, in San Juan Province, Argentina. In 1974, it was renamed to Carlos Ulrrico Cesco Astronomical Station ( ; EACUC).
Its primary observing facility is located i ...
at the
Leoncito Astronomical Complex
The El Leoncito Astronomical Complex (Spanish: Complejo Astronómico El Leoncito - CASLEO) is an astronomical observatory in the San Juan Province of Argentina. CASLEO is one of two observatories located within El Leoncito National Park, which i ...
in Argentina on 10 October 1974. It was later named after the discovering site.