An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1 Search : triple alpha process
triple alpha process
  فراروند ِ آلفای ِ سه‌تایی   
farâravand-e âlfâ-ye setâyi

Fr.: réaction triple alpha   

A chain of nuclear fusion reactions by which three helium nuclei (→ alpha particles) are transformed into → carbon. First two nuclei of helium collide, fuse, and form a nucleus of → beryllium: 4He + 4He ↔ 8Be, which is unstable and will decay back into two helium nuclei within a few 10-17 seconds. However, due to sufficiently high density and temperature in the stellar core, during a third collision between beryllium and helium, carbon is formed: 8Be + 4He → 12C + γ. The triple-alpha process is possible owing to the existence of the → Hoyle state. It is the main source of energy production in → red giants and → red supergiants in which the core temperature has reached at least 100 million K. Also called → Salpeter process.

triple; → alpha particle; → process.