Star chess player, one of seven (5,5)

I believe the answer is:

white dwarf

I'm a little stuck... Click here to teach me more about this clue!

'star' is the definition.
(white dwarf is a kind of star)

'chess player one of seven' is the wordplay.
'chess player' becomes 'white' (one of the two players in a game of chess).
'one of seven' becomes 'dwarf' (I can't justify this - if you can you should believe this answer much more).
'white'+'dwarf'='WHITE DWARF'

Can you help me to learn more?

(Another definition for white dwarf that I've seen is " Star".)

I've seen this clue in The Times and The Sunday Times.

Want a hint initially instead of a full solution? Install my app