Star caught in inferno, vaulting (4)
I believe the answer is:
nova
'star' is the definition.
(nova is a kind of star)
'caught in inferno vaulting' is the wordplay.
'caught in' indicates the answer is hidden within the clue.
'NOVA' can be found hidden inside 'inferno vaulting'.
(Other definitions for nova that I've seen before include "Star that becomes much brighter for short time" , "Exploding star" , "Kind of star" , "Star that suddenly increases in brightness" , "Suddenly bright star" .)