An Etymological Dictionary of Astronomy and Astrophysics

A → helium flash event that occurs during the → post-AGB phase.

Some of the central stars of planetary nebulae (→ CSPN) experience a final → thermal pulse after having achieved a → white dwarf configuration and begun their descent along a → white dwarf cooling track of nearly constant radius. During such a pulse, most of the hydrogen remaining in the star at pulse onset is incorporated into the helium-burning convective shell and completely burned. Following the pulse, the star swells briefly to → red giant dimensions
(Iben et al. 1983; ApJ 264, 605).

See also: → late; → helium; → flash.