- Omicron Ursae Majoris (ο Ursae Majoris, abbreviated Omicron UMa, ο UMa), formally named Muscida /ˈmjuːsɪdə/, is a star system in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of +3.35 and is located at a distance of around 179 light-years (55 parsecs) from the Sun. In 2012, an exoplanet designated Omicron Ursae Majoris Ab was found to be orbiting the primary.