
Helium flash
Brief thermal runaway nuclear fusion in the core of low-mass stars

Brief thermal runaway nuclear fusion in the core of low-mass stars
A helium flash is a very brief thermal runaway nuclear fusion of large quantities of helium into carbon through the triple-alpha process in the core of low-mass stars (between 0.8 solar masses (M☉) and 2.0 M☉) during their red giant phase. The Sun is predicted to experience a flash 1.2 billion years after it leaves the main sequence. A much rarer runaway helium fusion process can also occur on the surface of accreting white dwarf stars. Low-mass stars do not produce enough gravitational pressure to initiate normal helium fusion. As the hydrogen in the core is exhausted, some of the helium left behind is instead compacted into degenerate matter, supported against gravitational collapse by quantum mechanical pressure rather than thermal pressure. Subsequent hydrogen shell fusion further increases the mass of the core until it reaches temperature of approximately 100 million kelvins, which is hot enough to initiate helium fusion (or "helium burning") in the core. However, a property of degenerate...
Read on Wikipedia · Image RicHard-59, CC BY-SA 3.0
Open boosters, collect cards and trade them. Free to play.
Play for free