Mu Andromedae

μ Andromedae
Location of μ Andromedae (circled)
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]
Distance130 ± 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[7]
Mass2.21±0.09 M☉
Radius3.03±0.11 R☉
Luminosity40±3 L☉
Surface gravity (log g)3.99[8] cgs
Temperature8,320±150 K
Metallicity [Fe/H]+0.03[9] dex
Rotational velocity (v sin i)75[10] km/s
Age724±21 Myr
Other designations
μ Andromedae, μ And, Mu And, 37 Andromedae, BD+37°175, FK5 33, HD 5448, HIP 4436, HR 269, SAO 54281, PPM 65785
Database references
SIMBADdata

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]

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 2.2 times the mass of the Sun and three times the Sun's radius. The star is radiating about 4p times the luminosity of the Sun from its outer envelope at an effective temperature of 8,320 K,[7] giving it the characteristic white glow of an A-type star.[12] It is estimated to be about 724 million years old,[7] with a relatively high projected rotational velocity of 75 km/s.[10] Mu Andromedae has recently been found to be a binary system. The two stars orbit each other every 550.7 days.[6]

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  6. ^ a b Cite error: The named reference roettenbacher was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Maestro2013 was invoked but never defined (see the help page).
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  10. ^ a b Cite error: The named reference aaa463_2_671 was invoked but never defined (see the help page).
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