Meh. Then the question is oxymoronic, based on a category error. Its second half asks "
is the sun?", clearly requiring an ontological assement pertaining to an intrinsic trait or set of traits, but asking us - if I am to accept your definition of "colour" to assign a subjective value to an objective quantity. So either the question is badly posed - and therefore we need debate no further - or the definition of "colour" admits that it be well-posed. In that latter case, "colour" then either can be applied intrinsically (hence my previous post holds), or conversely is subjective, from which there is no point posting, because if I perceive the sun as red (or square) due to a vision impairment then it would be correct to say the sun
is red (or square). I would contend that squareness is not a quantity that can be empirically or theoretically applied to the sun (from a knowledge of stellar formation and magnetohydrodynamics), I am forced to conclude that my argument is the only valid one presented