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post main sequence star

(star evolved beyond its main sequence phase)

A post main sequence star is a star that has been through a main-sequence phase (the primary, lengthy hydrogen-burning fusion phase) and is proceeding through additional phases involving fusion of various elements. The phases it goes through, which depend upon the mass of the star, potentially include red-giant and asymptotic giant branch phases.

If sufficiently massive, fusion of helium into metals follows the main sequence, and beyond that, fusion of the resulting metals, including phases where layers of fusion occur, the heavier fusing elements closer to the center, a shell of hydrogen fusion at the top of the fusing core (the main sequence does not burn all the hydrogen).

Ultimately the post main sequence star becomes a compact objects, which one might classify as the last post-main-sequence phase.

(star type,stellar evolution)

Referenced by:
solar wind