helium flash


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helium flash

The explosive onset of helium burning (by the triple alpha process) in the degenerate core of an evolved star (a giant) when the core temperature reaches about 108 kelvin. The sudden increase in energy production causes a rapid rise in temperature, in turn increasing the reaction rate, but this runaway process eventually removes the degeneracy and the reaction once again becomes sensitive to the gas pressure. The helium flash occurs in stars of about one to two solar masses.

helium flash

[′hē·lē·əm ‚flash]
(astronomy)
The onset of runaway helium burning in the degenerate core of a red giant star and the resulting expansion of the core.
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References in periodicals archive ?
However, if the period is longer than a few months then we must wait until the re-expansion of the outer envelope of the evolving star after the helium flash (the AGB stage--see Part I).
Willson's research leads her to believe that the Sun will probably survive the helium flash with most of its mass intact.
After some 1,000 years, hydrogen burning resumes until the next helium flash 100,000 years later.
The helium flash brings heavier elements from the stellar interior to the surface.
The final helium flash renews the star with a vigorous source of energy, which causes both a tremendous brightening and a swelling in size.
So, in a sense, this final helium flash is really just a part of normal stellar evolution.
3 solar masses, core helium burning begins abruptly, engendering a brief thermonuclear runaway, or core helium flash.