An Etymological Dictionary of Astronomy and Astrophysics
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In evolutionary models of → low-mass and → intermediate-mass stars, the occurrence of a → helium shell flash just at the moment when the star is leaving the → asymptotic giant branch phase.

→ AGB; → final; → thermal; → pulse.

A → post-AGB star that undergoes a last → thermal pulse when it is already on the → white dwarf  → cooling track. The thermal pulse will expand the hot central star, whereby hydrogen will be ingested into the → helium burning shell. This will temporarily return the star to the → AGB phase it has previously left.

→ born; → again; → asymptotic giant branch; → star.

A fairly long-lived step in the evolution of → low-mass and → intermediate-mass stars when helium burning shifts from the center to a shell around the core. At this phase the stellar luminosity is provided almost entirely by → helium shell burning. The He-shell burning generally adds mass to the growing carbon/oxygen core, resulting in → degenerate matter due to its increasing density.

→ early; → AGB; → phase.