Ray makes star smile (7)
I believe the answer is:
sunbeam
'ray' is the definition.
(I know that sunbeam is a type of ray)
'star smile' is the wordplay.
'star' becomes 'sun' (the Sun is a star).
'smile' becomes 'beam' (to beam is to smile).
'sun'+'beam'='SUNBEAM'
'makes' acts as a link.
(Other definitions for sunbeam that I've seen before include "Bright ray -- bus name (anag)" , "Ray of natural light" , "Ray of solar light" , "Bright shaft of daylight" , "sheds a bit of light" .)