Heavenly body modelled with vase (6)
I believe the answer is:
saturn
'heavenly body' is the definition.
(Saturn is an example)
'modelled with vase' is the wordplay.
'modelled' becomes 'sat' ('sit' can be a synonym of 'model').
'with' means one lot of letters go next to another.
'vase' becomes 'urn' (both can mean a container).
'sat'+'urn'='SATURN'
(Other definitions for saturn that I've seen before include "Titan its moon" , "The dark planet" , "Runs at (anag) - Roman god" , "Massive body ringed" , "Sixth planet from the sun" .)