Archephysics and the Sun

As has been previously discussed, in On the Heavens, Aristotle introduces his Arche-element, leaving it nameless, though some believe that he has in mind Aether, while others have dubbed it Quintessence.  But, in On Generation and Corruption, though he does not explicitly state it, it seems very likely that the entity in question is the Sun.  If so, one problem that has arisen gets easily resolved.  That is, as has been previously discussed, his attribution of circular motion to the element leaves unaddressed the Center that a Circle presupposes.  But, of course, what he takes to be a body in orbit has since been proven to be a Center.  So, if his Arche-element is indeed the Sun, he has a more compelling, even if not definitive, Archephysics.  At minimum, there is strong textual evidence that Aether is not his 'fifth' element, and, therefore, that 'quintessence' accurately characterizes it.