Epsilon Muscae

Epsilon Muscae, Latinized as ε Muscae, is a red giant star of spectral type M5III in the constellation Musca. It is a 4th magnitude star, visible to the naked eye under good observing conditions. It is about 330 light-years from the Earth.

Originally a main-sequence star of around 2 solar masses, Epsilon Muscae is now on the asymptotic giant branch and has expanded to 117 times the Sun's diameter and 1,700 its luminosity. It is a semiregular variable, varying between visual magnitudes 4.0 and 4.3 in eight distinct periods ranging from a month to over half a year in length. Its distance from the Earth is about the same as the Lower Centaurus–Crux subgroup of the Scorpius–Centaurus association, although it is moving much faster at around 100 km/s and does not share a common origin.