Beta Muscae
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 340 ± 13 light-years (105 ± 4 parsecs) from the Earth.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Musca |
| Right ascension | 12h 46m 16.80410s |
| Declination | –68° 06′ 29.2164″ |
| Apparent magnitude (V) | 3.05 (3.51 + 4.01) |
| Characteristics | |
| Spectral type | B2 V + B3 V |
| U−B color index | –0.766 |
| B−V color index | –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 | 340 ± 10 ly (105 ± 4 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 M☉ |
| Luminosity | 1,892 L☉ |
| Age | 15.1 ± 1.2 Myr |
| β Mus B | |
| Mass | 6.40 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
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.