Eta Muscae

The two main components of this system form a double-lined spectroscopic binary with a period of 2.4 days in a circular orbit. They are a detached eclipsing binary with a spectral type of B8V and a brightness that dips by 0.05 magnitude once per orbit. This pair consists of two components of similar mass and type.

Further away from the primary system are stars of magnitude 7.3 and 10, designated Eta Muscae B and C. It is unclear if these stars are gravitationally–bound to the main pair. Evidence for an additional component has been found with a 30-year cycle in the orbital behavior of the main pair. The data suggests an orbital eccentricity of 0.29 for this suspected component, Eta Muscae D.