Binary star in the constellation Andromeda
μ Andromedae Location of μ Andromedae (circled)
Observation dataEpoch J2000 Equinox J2000 Constellation Andromeda Right ascension 00h 56m 45.209s [ 1] Declination +38° 29′ 57.60″[ 1] Apparent magnitude (V)3.87[ 2] Characteristics Spectral type A5 V[ 3] U−Bcolor index +0.15[ 2] B−Vcolor index +0.12[ 2] Variable type RS CVn [ 4] Astrometry Radial velocity (Rv )+7.6[ 5] km/s Proper motion (μ)RA: +151.021mas /yr [ 1] Dec.: +34.800mas /yr [ 1] Parallax (π)26.7046± 0.6467 mas [ 1] Distance 122 ± 3 ly pc ) Absolute magnitude (MV )+0.86[ 6] Orbit [ 4] Period (P)± 0.2 dSemi-major axis (a)± 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)168.9± 0.3° Semi-amplitude 1 )11.1± 0.5 km/s Details[ 7] Mass ± 0.09M ☉ Radius ± 0.11R ☉ Luminosity ± 3L ☉ Surface gravity (log g )3.99[ 8] cgs Temperature ± 150K Metallicity [Fe/H] +0.03[ 9] dex Rotational velocity (v sin i )75[ 10] Age ± 21Myr Other designations μ Andromedae, μ And, Mu And ,37 Andromedae ,BD +37°175FK5 33HD 5448HIP 4436HR 269SAO 54281PPM 65785[ 11] Database references SIMBAD data
Mu Andromedae is abinary star system in the northernconstellation ofAndromeda . ItsBayer designation isLatinized fromμ Andromedae , and abbreviatedMu And orμ And , respectively. The system has anapparent visual magnitude of 3.87,[ 2] parallax measurements, it is located at a distance of approximately 122light-years (37parsecs ) fromEarth .[ 1] Mirach to the southwest and theAndromeda Galaxy (M31) to the northeast.[ 12]
Thespectrum of this star matches astellar classification of A5 V,[ 3] 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 40 times the luminosity of the Sun from itsouter envelope at aneffective temperature of 8,320 K,[ 7] [ 13] [ 7] projected rotational velocity of 75 km/s.[ 10]
In 2007, Mu Andromedae was found to be atidally-locked closebinary system with an unseen companion. The two stars orbit each other every 550.7 days. The tidal interactions have spun up the primary star, causing it to becomemagnetically active and host unusually strongstarspots .[ 4]
InChinese ,奎宿 Kuí Sù Legs (asterism)η Andromedae ,65 Piscium ,ζ Andromedae ,ε Andromedae ,δ Andromedae ,π Andromedae ,ν Andromedae ,β Andromedae ,σ Piscium ,τ Piscium ,91 Piscium ,υ Piscium ,φ Piscium ,χ Piscium andψ¹ Piscium . Consequently, theChinese name for μ Andromedae itself is奎宿八 Kuí Sù bā the Eighth Star of Legs .)[ 14]
^a b c d e Brown, A. G. A. ; et al. (Gaia collaboration) (2021)."Gaia Early Data Release 3: Summary of the contents and survey properties" .Astronomy & Astrophysics 649 : A1.arXiv :2012.01533 Bibcode :2021A&A...649A...1G .doi :10.1051/0004-6361/202039657 S2CID 227254300 . (Erratum: doi :10.1051/0004-6361/202039657e ) . Gaia EDR3 record for this source atVizieR .^a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars",Communications of the Lunar and Planetary Laboratory ,4 (99): 99,Bibcode :1966CoLPL...4...99J . ^a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications",Astronomical Journal ,74 :375– 406,Bibcode :1969AJ.....74..375C ,doi :10.1086/110819 . ^a b c Roettenbacher, R. M.; et al. (2016), "No Sun-like dynamo on the active star ζ Andromedae from starspot asymmetry",Nature ,533 (7602):217– 220,arXiv :1709.10107 Bibcode :2016Natur.533..217R ,doi :10.1038/nature17444 ,PMID 27144357 ,S2CID 4466687 . ^ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities",Carnegie Institute Washington D.C. Publication ,Carnegie Institute of Washington D.C. ,Bibcode :1953GCRV..C......0W . ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation",Astronomy Letters ,38 (5): 331,arXiv :1108.4971 Bibcode :2012AstL...38..331A ,doi :10.1134/S1063773712050015 ,S2CID 119257644 . ^a b c Maestro, V.; et al. (2013), "Optical interferometry of early-type stars with PAVO@CHARA - I. Fundamental stellar properties",Monthly Notices of the Royal Astronomical Society ,434 (2): 1321,arXiv :1306.5937 Bibcode :2013MNRAS.434.1321M ,doi :10.1093/mnras/stt1092 S2CID 2361434 . ^ Malagnini, M. L.; Morossi, C. (November 1990), "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars",Astronomy and Astrophysics Supplement Series ,85 (3):1015– 1019,Bibcode :1990A&AS...85.1015M . ^ Gardiner, R. B.; Kupka, F.; Smalley, B. (July 1999), "Testing convection theories using Balmer line profiles of A, F, and G stars",Astronomy and Astrophysics ,347 :876– 890,Bibcode :1999A&A...347..876G . ^a b Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions",Astronomy and Astrophysics ,463 (2):671– 682,arXiv :astro-ph/0610785 Bibcode :2007A&A...463..671R ,doi :10.1051/0004-6361:20065224 ,S2CID 18475298 . ^ "mu. And" ,SIMBAD Centre de données astronomiques de Strasbourg , retrieved2025-03-23 ^ Reddy, Francis (2011),Celestial Delights: The Best Astronomical Events Through 2020 ISBN 978-1461406099 ^ "The Colour of Stars" ,Australia Telescope, Outreach and Education ,Commonwealth Scientific and Industrial Research Organisation , December 21, 2004, archived fromthe original on March 18, 2012, retrieved2012-01-16 .^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日 Archived 2016-03-03 at theWayback Machine
