Beta Muscae

Beta Muscae

Template:Location mark Location of β Musca (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Musca
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	3.05 (3.51 + 4.01)
Characteristics
Spectral type	B2 V + B3 V
U−B Template:Engvar	−0.766
B−V Template:Engvar	−0.198
Astrometry
Radial velocity (Rv)	+42 km/s
Proper motion (μ)	RA: −41.97 mas/yr Dec.: −8.89 mas/yr
Parallax (π)	9.55±0.41 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	−2.06
Orbit
Period (P)	194.28 yr
Semi-major axis (a)	0.969″
Eccentricity (e)	0.598
Inclination (i)	37.1°
Longitude of the node (Ω)	349.4°
Periastron epoch (T)	1857.50
Argument of periastron (ω) (secondary)	209.0°
Details
β Mus A
Mass	7.35 Template:Solar mass
Luminosity	1,892 Template:Solar luminosity
Age	Myr
β Mus B
Mass	6.40 Template:Solar mass
Metallicity [Fe/H]	{{{metal_fe2}}} dex
Other designations
Template:Odlist
Database references
SIMBAD	data

Beta Muscae, Latinized from β Muscae, is a binary star in the southern circumpolar constellation of Musca. With a combined apparent visual magnitude of 3.07, it is the second brightest star (or star system) in the constellation. Judging by the parallax results, it is located at a distance of roughly from the Earth.

This is a binary star system with a period of about 194 years at an orbital eccentricity of 0.6. As of 2007, the two stars had an angular separation of 1.206 arcseconds at a position angle of 35°. The components are main sequence stars of similar size and appearance. The primary component, β Muscae A, has an apparent magnitude of 3.51, a stellar classification of B2 V, and about 7.35 times the Sun's mass. The secondary component, β Muscae B, has an apparent magnitude of 4.01, a stellar classification of B3 V, and is about 6.40 times the mass of the Sun.

This is a confirmed member of the Scorpius–Centaurus association, which is a group of stars with similar ages, locations, and trajectories through space, implying that they formed together in the same molecular cloud. Beta Muscae is considered a runaway star system as it has a high peculiar velocity of 43.9 km s⁻¹ relative to the normal galactic rotation. Runaway stars can be produced through several means, such as through an encounter with another binary star system. Binary systems form a relatively small fraction of the total population of runaway stars.