Analyst on origins of stars embodying Sagittarius (10)
I believe the answer is:
researcher
'analyst' is the definition.
(I've seen this before)
'on origins of stars embodying sagittarius' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'origins of' indicates taking the first letters.
'sagittarius' becomes 'archer' (I've seen this in another clue).
The first letters of 'stars embodying' is 'se'.
're'+'se'+'archer'='RESEARCHER'
(Other definitions for researcher that I've seen before include "Person investigating" , "One seeks information" , "I investigate" , "One investigating" , "analyst" .)