or might it have a solid core because it is so massive or perhaps a core of both solids and gases?
Nothing is known about the interior of the sun, but nobody will admit it. For instance, everybody assumes the sun is powered by fusion. If that were true, the inside would be hotter than the outside, and the reverse is true. People believe a lot of nonsense like that, where a casual observation disproves their theories, but they only insult you if you point it out.