By determining the moon's distance and orbit around Xena, scientists can calculate how heavy Xena is. For example, the faster a moon goes around a planet, the more massive a planet is.
Oh, whew:
The International Astronomical Union, a group of scientists responsible for naming planets, is deciding on formal names for Xena and Gabrielle.
Maybe they need to figure out what Xena and Gabrielle's names would have been once they got transferred to Roman mythology.