Astronomer captures alien for features editor (13)

I believe the answer is:
cosmetologist
'features editor' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'astronomer captures alien for' is the wordplay.
'astronomer' becomes 'cosmologist' (cosmologist is a kind of astronomer).
'captures' indicates putting letters inside.
'alien for' becomes 'et' (I can't justify this - if you can you should believe this answer much more).
'cosmologist' placed around 'et' is 'COSMETOLOGIST'.
Can you help me to learn more?
(Another definition for cosmetologist that I've seen is " one in Boots?".)
