Mu Andromedae
Binary star in the constellation Andromeda / From Wikipedia, the free encyclopedia
Mu Andromedae (Mu And, μ Andromedae, μ And) is the Bayer designation for a star in the northern constellation of Andromeda. It has an apparent visual magnitude of 3.87,[2] making it readily visible to the naked eye. Based upon parallax measurements, it is approximately 130 light-years (40 parsecs) from Earth.[1] In the constellation, the star is situated about halfway between the bright star Mirach to the southwest and the Andromeda Galaxy (M31) to the northeast.[11]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Andromeda |
Right ascension | 00h 56m 45.21211s[1] |
Declination | +38° 29′ 57.6380″[1] |
Apparent magnitude (V) | 3.87[2] |
Characteristics | |
Spectral type | A5 V[3] |
U−B color index | +0.15[2] |
B−V color index | +0.12[2] |
Astrometry | |
Radial velocity (Rv) | +7.6[4] km/s |
Proper motion (μ) | RA: +153.48[1] mas/yr Dec.: +36.49[1] mas/yr |
Parallax (π) | 25.14 ± 0.86 mas[1] |
Distance | 130 ± 4 ly (40 ± 1 pc) |
Absolute magnitude (MV) | +0.86[5] |
Orbit[6] | |
Period (P) | 550.7 ± 0.2 d |
Semi-major axis (a) | 46.66 ± 0.06 mas |
Eccentricity (e) | 0.8405 ± 0.0009 |
Inclination (i) | 52.5 ± 0.3° |
Longitude of the node (Ω) | −17.6 ± 0.2° |
Periastron epoch (T) | 55765.45 ± 0.04 MJD |
Argument of periastron (ω) (secondary) | 168.9 ± 0.3° |
Semi-amplitude (K1) (primary) | 11.1 ± 0.5 km/s |
Details | |
Mass | 2.0[7] M☉ |
Radius | 2.4[7] R☉ |
Luminosity | 21[7] L☉ |
Surface gravity (log g) | 3.99[7] cgs |
Temperature | 7,959[8] K |
Metallicity [Fe/H] | +0.03[8] dex |
Rotational velocity (v sin i) | 75[9] km/s |
Age | 600[10] Myr |
Other designations | |
Database references | |
SIMBAD | data |
The spectrum of this star matches a stellar classification of A5 V,[3] indicating that it is an A-type main sequence star. It has double the mass of the Sun and 2.4 times the Sun's radius.[7] The star is radiating about 21[7] times the luminosity of the Sun from its outer envelope at an effective temperature of 7,959 K,[8] giving it the characteristic white glow of an A-type star.[12] It is estimated to be about 600 million years old,[10] with a relatively high projected rotational velocity of 75 km/s.[9] Mu Andromedae has recently been found to be a binary system. The two stars orbit each other every 550.7 days.[6]