Rayets are dead suns and there are various different types of them, the most common are white rayets. various different suns dying make different rayets of different colors.

White Rayets are the most common Rayet out there. They are created from dying orange and yellow and red giants. White rayets are very dense, made mostly of dead sun material. Some white rayets are actually blue but they aren't blue rayets.  They are named with "00" in the middle like JA00