Extraordinarily remote heavenly body (6)
I believe the answer is:
Here is my best explanation:
'heavenly body' is the definition.
(meteor is a kind of heavenly body)
'extraordinarily remote' is the subsidiary indication.
'extraordinarily' indicates anagramming the letters (I've seen this in other clues).
'remote' anagrammed gives 'meteor'.
(Other definitions for meteor that I've seen before include "It causes a streak of light in the night sky", "Remote (anag)", "Body entering earth's atmosphere", "Space traveller", "rock falling to earth", "Small piece of matter in the solar system", "space traveller", "Glowing body entering atmosphere", "Space body" and "Streak of light in the night sky".)