993 Moultona, provisional designation ', is a Koronian
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
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from the outer regions of the asteroid belt, approximately in diameter. It was discovered on 12 January 1923, by astronomer
George Van Biesbroeck
George A. Van Biesbroeck (or Georges-Achille Van Biesbroeck, , January 21, 1880 – February 23, 1974) was a Belgian–American astronomer. He worked at observatories in Belgium, Germany and the United States. He specialized in the observation o ...
at the Yerkes Observatory in Williams Bay, Wisconsin, in the United States. The likely elongated asteroid has a
rotation period
The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...
of 5.3 hours. It was named after American astronomer Forest Ray Moulton.
Orbit and classification
''Moultona'' is a core member of the
Koronis family ]
The Koronis or Koronian family (), also known as the Lacrimosa family, is a very large asteroid family of S-type asteroid, stony asteroids, located in the Kirkwood gap, outer region of the asteroid belt. They are thought to have been formed at le ...
(), a very large outer
asteroid family
An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An a ...
with nearly co-planar ecliptical orbits. It orbits the Sun in the