Heavenly streaker (5)
I believe the answer is:
comet
'heavenly streaker' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for comet that I've seen before include "Early jetliner" , "Small extraterrestrial body" , "Rudolph's companion" , "Dancer's colleague" , "Frozen body" .)