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EntityQ259854· pop 38· linked from 688 articles

cloud of gas or a trail around a comet or asteroid

Wikidata facts

Part of
comet
Show 2 more facts
Commons category
Coma (cometary)
different from
Koma
Sources (1)

via Wikidata · CC0

~7 min read

Encyclopedic overview

Structure of Comet Holmes in infrared, as seen by an infrared space telescope

The coma is the nebulous envelope around the nucleus of a comet, formed when the comet passes near the Sun in its highly elliptical orbit. As the comet warms, parts of it sublimate; this gives a comet a diffuse appearance when viewed through telescopes and distinguishes it from stars. The word coma comes from the Greek κόμη (kómē), which means "hair" and is the origin of the word comet itself.

Excerpted from Wikipedia’s “coma” article, available under the CC BY-SA 4.0 licence.