Epsilon Muscae, Latinized as ε Muscae, is a

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...

star of spectral type M5III in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Musca Musca () is a small constellation in the deep southern sky. It was one of 12 constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman, and it first appeared on a celestial globe in dia ...

. Originally a main-sequence star of around 1.5 to 2

solar mass The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

es, it is now on the

asymptotic giant branch The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (about 0.5 to 8 solar masses) lat ...

and has now expanded to 130 times the Sun's diameter and 1800 to 2300 its luminosity. It is a semiregular variable, varying in eight distinct periods ranging from a month to over half a year in length, with the largest amplitude being of almost half a magnitude from the mean of 4.06. It is located around 300 light-years distant, the same distance as the Lower Centaurus–Crux subgroup of the

Scorpius–Centaurus association The Scorpius–Centaurus association (sometimes called Sco–Cen or Sco OB2) is the nearest OB association to the Sun. This stellar association is composed of three subgroups (Upper Scorpius, Upper Centaurus–Lupus, and Lower Centaurus–Crux) ...

, although it is moving much faster at around 100 km/s and does not share a common origin.

References

{{DEFAULTSORT:Epsilon Muscae M-type giants Asymptotic-giant-branch stars Semiregular variable stars Musca (constellation) Muscae, Epsilon Durchmusterung objects 106849 059929 4671