Small actor's heavenly body (5,4)

I believe the answer is:

dwarf star

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

'heavenly body' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'small actor's' is the wordplay.
'small' becomes 'dwarf' (similar in meaning).
'actor' becomes 'star' (star is a kind of actor).
'dwarf'+'star'='DWARF STAR'

Can you help me to learn more?

(Another definition for dwarf star that I've seen is " Sun?".)

I've seen this clue in the Sydney Morning Herald.

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