Extinct comet
An extinct comet is a comet that has lost its surface ice or become buried in dust, so it no longer forms a coma.
An extinct comet is the nucleus of a comet that no longer shows activity. After many passages near the Sun, a comet may have lost most of its ice, or a crust of dust and organic matter may have built up and sealed the remaining ice inside. The result looks like a dark asteroid.
Some near-Earth asteroids are thought to be extinct comets, because they have comet-like orbits and very low albedos. Examples include 3552 Don Quixote, which turned out to have faint activity when observed in infrared light, and possibly 2003 EH1, linked to the Quadrantid meteor shower.
Estimates suggest a few per cent of near-Earth asteroids may be dormant or extinct comets. Distinguishing them from ordinary asteroids helps us understand the sources of near-Earth objects and of meteor showers. A meteoroid stream may continue to orbit long after its parent has stopped producing new dust.
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Level: Expert Advanced