Binary star system in the constellation Andromeda
Pi Andromedae Location of π Andromedae (circled)
Observation dataEpoch J2000 Equinox J2000 Constellation Andromeda Right ascension 00h 36m 52.85132s [ 1] Declination +33° 43′ 09.6363″[ 1] Apparent magnitude (V)4.36[ 2] [ 3] Characteristics Spectral type B5 V[ 4] B5 V + B5 V [ 3] U−Bcolor index –0.55[ 2] B−Vcolor index –0.16[ 2] Astrometry Radial velocity (Rv )+8.7[ 5] km/s Proper motion (μ)RA: mas /yr [ 1] Dec.: mas /yr [ 1] Parallax (π)5.6563± 0.1474 mas [ 1] Distance 580 ± 20 ly pc ) Orbit [ 6] Period (P)± 0.06 dSemi-major axis (a)± 0.05 mas Eccentricity (e)0.542± 0.006 Inclination (i)103.0± 0.2° Longitude of the node (Ω)94.7± 0.2° Periastron epoch (T)7717.7± 0.4 Argument of periastron (ω)170.7± 0.7° Semi-amplitude 1 )47.50± 0.53 km/s Semi-amplitude (K2 )117.4± 2.8 km/s Details[ 7] A Mass 5.8[ 6] M ☉ Radius 4.7 R ☉ Luminosity 1,000 L ☉ Surface gravity (log g )4.10[ 4] cgs Temperature 15,000 K Metallicity [Fe/H] –0.20[ 4] dex Rotational velocity (v sin i )25[ 8] Age 80 Myr B Mass 4.8[ 6] M ☉ Radius 4.7 R ☉ Luminosity 1,000 L ☉ Temperature 15,000 K Other designations Pi And, π Andromedae, π And ,29 Andromedae ,BD +32°101FK5 18HD 3369HIP 2912HR 154SAO 54033PPM 65480ADS 513Database references SIMBAD data
Pi Andromedae is abinary star [ 3] constellation ofAndromeda . ItsBayer designation islatinized fromπ Andromedae , and abbreviatedPi And orπ And , respectively. With anapparent visual magnitude of 4.4,[ 2] visible to the naked eye . Based onparallax measurements, it is located at a distance of approximately 580light-years (180parsecs ) fromEarth .[ 1]
π Andromedae in optical light The pair is classified as a blue-whiteB-type main sequence dwarf , with anapparent magnitude of +4.34. It is aspectroscopic binary with an orbital period of 143.5 days and aneccentricity of 0.54.[ 6]
The spectroscopic binary forms a triple system withBD+32 102 , a magnitude 8.6 star located 35.9arcseconds away.[ 3] arcseconds separation is an 11th magnitude companion that is just located on the same line of sight, but at a very different distance from us.
InChinese ,奎宿 Kuí Sù Legs (asterism)η Andromedae ,65 Piscium ,ζ Andromedae ,ε Andromedae ,δ Andromedae ,ν Andromedae ,μ Andromedae ,β Andromedae ,σ Piscium ,τ Piscium ,91 Piscium ,υ Piscium ,φ Piscium ,χ Piscium andψ¹ Piscium . Consequently, theChinese name for π Andromedae itself is奎宿六 Kuí Sù liù the Sixth Star of Legs .)[ 9]
^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 c d Eggleton, P. P.; Tokovinin, A. A. (September 2008)."A catalogue of multiplicity among bright stellar systems" .Monthly Notices of the Royal Astronomical Society .389 (2):869– 879.arXiv :0806.2878 Bibcode :2008MNRAS.389..869E .doi :10.1111/j.1365-2966.2008.13596.x S2CID 14878976 . ^a b c Cenarro, A. J.; et al. (January 2007), "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters",Monthly Notices of the Royal Astronomical Society 374 (2):664– 690,arXiv :astro-ph/0611618 Bibcode :2007MNRAS.374..664C ,doi :10.1111/j.1365-2966.2006.11196.x S2CID 119428437 . ^ Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities",Carnegie Institute Washington D.C. Publication , Washington: Carnegie Institution of Washington,Bibcode :1953GCRV..C......0W . ^a b c d Hummel, C. A.; et al. (July 1995). "Orbits of Small Angular Scale Binaries Resolved with the Mark III Interferometer".Astronomical Journal .110 : 376.Bibcode :1995AJ....110..376H .doi :10.1086/117528 . ^ "Pi And" .stars.astro.illinois.edu . Retrieved2025-02-06 .^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars",The Astrophysical Journal ,573 (1):359– 365,Bibcode :2002ApJ...573..359A ,doi :10.1086/340590 ^ (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
