Selene was a goddess of the moon (or later the actual MOON itself) just as her brother Helios was the god of the sun and then Artemis and Apollo sort of adapted and evolved into their powers/were twin associations. Artemis and Apollo were gods where as Helios and Selene were children of Titans and more literal representations (although Selene does end have an amorous relationship with Zeus).

So uh, short answer is yes! Yes, she is!