Stellar Mimicry

Is there any tangible difference between Solar Physiology and Stellar Physiology? AFAIK "solar" is simply an adjective for the noun "sun", which may be a proper noun that's an alternative way of referring to the Sun or a common noun referring to any star (but especially one that is at the center of its own system of planets and other satellite bodies). In other words, the distinction seems to be arbitrary due to lack of any substantial differences - or to put it another way, as it stands there's nothing to prove that the sets represented by the two powers' examples aren't entirely identical rather than one comprising only a partial subset of the other.

If someone had Stellar Physiology could they shapeshift into other things or lifeforms?