Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Musca |
Right ascension | 12h 37m 11.01789s [1] |
Declination | –69° 08′ 08.0332″ [1] |
Apparent magnitude (V) | +2.69 [2] |
Characteristics | |
Spectral type | B2 IV–V [3] |
U−B color index | −0.854 [2] |
B−V color index | −0.219 [2] |
Variable type | β Cep [4] |
Astrometry | |
Radial velocity (Rv) | +13 [5] km/s |
Proper motion (μ) |
RA: −40.20
[1]
mas/
yr Dec.: −12.80 [1] mas/ yr |
Parallax (π) | 10.34 ± 0.11 mas [1] |
Distance | 315 ± 3
ly (97 ± 1 pc) |
Absolute magnitude (MV) | –2.2 [6] |
Details | |
Mass | 8.8±0.1 [3] M☉ |
Radius | 4.8 [7] R☉ |
Luminosity | 4,000 [6] L☉ |
Surface gravity (log g) | 4.06 [6] cgs |
Temperature | 21,400 [6] K |
Rotational velocity (v sin i) | 114 [8] km/s |
Age | 18.3±3.2 [3] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Alpha Muscae, Latinized from α Muscae, is a star in the southern circumpolar constellation of Musca. With an apparent visual magnitude of +2.7, [2] it is the brightest star in the constellation. The distance to this star has been determined using parallax measurements, giving an estimate of about 315 light-years (97 parsecs) from Earth. [1]
With a stellar classification of B2 IV-V, [3] this star appears to be in the process of evolving away from the main sequence of stars like the Sun and turning a subgiant star, as the supply of hydrogen at its core becomes exhausted. It is larger than the Sun, with nearly nine [3] times the mass and almost five [7] times the radius. This star is radiating around 4,000 [6] times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 21,400 K, [6] giving it the blue-white hue of a B-type star. [10]
Alpha Muscae appears to be a Beta Cephei variable star. Telting and colleagues report it as a Beta Cephei with a high degree of confidence as they found regular pulsations in its spectrum in a high-resolution spectroscopy study published in 2006, [4] although Stankov and Handler (2005) listed it as a poor or rejected candidate in their Catalog of Galactic β Cephei Stars. [8] The International Variable Star Index lists it as a Beta Cephei variable which varies in brightness from magnitude 2.68 to 2.73, with a period of 2.17 hours. [12] Alpha Muscae is rotating rapidly with a projected rotational velocity of 114 km s−1 [8] and has an estimated age of about 18 million years. [3]
This star is a proper motion member of the Lower Centaurus–Crux sub-group in the Scorpius–Centaurus OB association, the nearest such association of co-moving massive stars to the Sun. [6] Alpha Muscae has a peculiar velocity of 10 km s−1, which, while high, is not enough for it to be considered a runaway star. [3]