Phaethusa

Phaethusa (Φαεθουσα) - a minor nymph-goddess daughter of Helios and Neaera. She has a twin sister, Lampetia, who she watches over the herds of her father with. She and her sister were granted the physical form of goddesses, but their natural forms are that of a nymph. Her name means "radiance," and she is the personification of blinding rays of sun.