Team with genuine line-up of stars (8)
I believe the answer is:
sidereal
'of stars' is the definition.
(sidereal means relating to the stars)
'team with genuine' is the wordplay.
'team' becomes 'side' (both can mean a sports team).
'with' is a charade indicator (letters next to each other).
'genuine' becomes 'real' (similar in meaning).
'side'+'real'='SIDEREAL'
'line-up' acts as a link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for sidereal that I've seen before include "Relating to the constellations" , "Of the stars or constellations" , "Relating to the distant stars" , "involving stars" , "Like stars" .)