What fusion mechanism is primarily used by stars above about $1.3$ solar masses?

Answer

CNO cycle

Stars above about $1.3$ solar masses typically generate energy primarily through the CNO cycle, which is a highly efficient process dependent on trace amounts of heavier elements.

What fusion mechanism is primarily used by stars above about $1.3$ solar masses?

#Videos

Low Mass Stars: Crash Course Astronomy #29 - YouTube

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