Astrophysics (Index)About

carbon star

(C, C-type star)
(star with more carbon than oxygen in its atmosphere)

A carbon star is a star with more carbon than oxygen in its stellar atmosphere. The spectral class C (for C-type star) indicates a star with molecular carbon lines, indicating such a star. Carbon and oxygen in a star's atmosphere forms carbon monoxide, and if carbon is left over, other carbon compounds are formed, giving the star a red appearance (most stars, including the Sun, have more oxygen than carbon in their atmospheres). One way stars form more-than-usual carbon is thought to be asymptotic giant branch stars with helium that produce carbon through helium fusion. Another way is accretion in a binary. Carbon stars can emit carbon in their stellar wind, leading to carbon in cosmic dust. Some related terms:

(For each of these terms, whether it can be called a subclass of carbon star, versus some other star type that has some carbon is a matter of semantics: the term carbon star is probably often used specifically for certain well-known types/scenarios.)

(star type,carbon,spectral class)
Further reading:

Referenced by pages:
binary star
chemically peculiar star (CP star)
PAH emissions
rare designator prefixes
spectral class