How do stars die?

Stars begin their lives when hydrogen fusion ignites in their dense, hot cores. Once that process starts, it’s game on. The gravitational pull of all the mass of the star tries to squeeze it down into a tiny point, but the energy released by fusion pushes outward, creating a delicate balance that can persist for millions or even trillions of years.

Small stars live an incredibly long time. Because of their small stature, they don’t need a lot of energy to balance the inward gravitational pull, so they only sip at their hydrogen reserves. In a bonus boost, the atmospheres of these stars constantly circulate, pulling fresh hydrogen down from the outer layers into the core, where it can fuel the continuing fire. 

All told, a typical red dwarf star will happily burn hydrogen in its core for trillions of years. Not too shabby.

As these small stars age, they steadily become brighter until they just sort of vaguely sputter out, becoming an inert, boring lump of helium and hydrogen just hanging around the universe minding nobody’s business but their own. 



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