Check reduced rotation of star to see planet (5)
I believe the answer is:
venus
'planet' is the definition.
(Venus is a planet)
'check reduced rotation of star' is the wordplay.
'check' becomes 'vet' (to vet someone is to check their background).
'reduced' means to remove the last letter.
'rotation of star' becomes 'nus' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'vet' with its last letter removed is 've'.
've'+'nus'='VENUS'
'to see' is the link.
Can you help me to learn more?
(Other definitions for venus that I've seen before include "Brightest planet" , "Heavenly body" , "not really a star" , "Planet; goddess" , "Second nearest planet to the sun" .)