Dawn is gold and yellow captured by artist (6)
I believe the answer is:
aurora
'dawn' is the definition.
('aurora' can be a synonym of 'dawn')
'gold and yellow captured by artist' is the wordplay.
'gold' becomes 'au' (Au is the chemical symbol for gold).
'and' says to put letters next to each other.
'yellow' becomes 'or' (heraldic term).
'captured by' indicates putting letters inside.
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'or' put into 'ra' is 'rora'.
'au'+'rora'='AURORA'
'is' is the link.
(Other definitions for aurora that I've seen before include "Northern or southern lights" , "Polar display" , "7 ... borealis, ... lights" , "Coloured light in the sky" , "Dawn goddess; polar lights" .)