▁a ▁white ▁d war f . ▁White ▁d war f ▁stars , ▁if ▁they ▁have ▁a ▁near ▁companion , ▁may ▁then ▁become ▁Type   I a ▁super nov ae . ▁ ▁A ▁much ▁larger ▁star , ▁however , ▁is ▁massive ▁enough ▁to ▁create ▁temper atures ▁and ▁press ures ▁needed ▁to ▁cause ▁the ▁carbon ▁in ▁the ▁core ▁to ▁begin ▁to ▁f use ▁when ▁the ▁star ▁contract s ▁at ▁the ▁end ▁of ▁the ▁hel ium - burn ing ▁stage . ▁The ▁cores ▁of ▁these ▁massive ▁stars ▁become ▁layer ed ▁like ▁on ions ▁as ▁progress ively ▁heav ier ▁atomic ▁nuc lei ▁build ▁up ▁at ▁the ▁center , ▁with ▁an ▁outer most ▁layer ▁of ▁hydro gen ▁gas , ▁surrounding ▁a ▁layer ▁of ▁hydro gen ▁f using ▁into ▁hel ium , ▁surrounding ▁a ▁layer ▁of ▁hel ium ▁f using ▁into ▁carbon ▁via ▁the ▁triple - alpha ▁process , ▁surrounding ▁layers ▁that ▁f use ▁to ▁progress ively ▁heav ier ▁elements . ▁As ▁a ▁star ▁this ▁massive ▁evol ves , ▁it ▁under go es ▁repeated ▁stages ▁where ▁fusion ▁in ▁the ▁core ▁stops , ▁and ▁the ▁core ▁col laps es ▁until ▁the ▁pressure ▁and ▁temperature ▁are ▁sufficient ▁to ▁begin ▁the ▁next ▁stage ▁of ▁fusion , ▁reign iting ▁to ▁halt ▁collapse . ▁ ▁{ | ▁class =" wik itable " ▁| + ▁Core - burn ing ▁nuclear ▁fusion ▁stages ▁for ▁a ▁ 2 5 - sol ar ▁mass ▁star ▁! row span =" 2 " | ▁Process ▁! row span =" 2 " | ▁Main ▁fuel ▁! row span =" 2 "