Star in the constellation Pegasus
2 Pegasi Location of 2 Pegasi (circled)
Observation dataEpoch J2000 Equinox J2000 Constellation Pegasus Right ascension 21h 29m 56.89545s [ 1] Declination 23° 38′ 19.8170″[ 1] Apparent magnitude (V)4.52[ 2] Characteristics Evolutionary stage AGB [ 3] Spectral type M1+III[ 4] U−Bcolor index +1.93[ 5] B−Vcolor index +1.62[ 5] Astrometry Radial velocity (Rv )−18.92[ 6] km/s Proper motion (μ)RA: +24.74[ 1] mas /yr Dec.: +3.63[ 1] mas /yr Parallax (π)8.28± 0.18 mas [ 1] Distance 394 ± 9 ly pc ) Absolute magnitude (MV )−0.89[ 2] Details Mass 1.2[ 7] M ☉ Radius 55[ 8] R ☉ Luminosity 646[ 9] L ☉ Surface gravity (log g )1.57[ 7] cgs Temperature 3,921[ 9] K Metallicity [Fe/H] −0.16[ 7] dex Other designations 2 Peg ,NSV 25624BD +23°4325FK5 1565GC 30109HD 204724HIP 106140HR 8225SAO 89752CCDM J21299+2338AWDS J21299+2338A[ 10] Database references SIMBAD data
2 Pegasi is a single[ 11] star in theconstellation Pegasus , located approximately 394 light years away from the Sun based on parallax.[ 1] naked eye as a faint, red-hued star with anapparent visual magnitude of 4.52.[ 2] radial velocity of −19 km/s.[ 6] angular separation of″ [ 12]
This is an agingred giant star with astellar classification of M1+III,[ 4] asymptotic giant branch ,[ 3] evolved away from themain sequence . The star has expanded to an estimated 55 times theradius of the Sun .[ 8] luminosity of the Sun from its enlargedphotosphere at aneffective temperature ofK
It is the 2nd star numbered byFlamsteed in order ofright ascension . In the 1795 French-language Fortin-Flamsteed edition of theAtlas Coelestis , 2 Pegasi is labelled with the letter "f".[ 13]
^a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction".Astronomy and Astrophysics .474 (2):653– 664.arXiv :0708.1752 Bibcode :2007A&A...474..653V .doi :10.1051/0004-6361:20078357 .S2CID 18759600 . Vizier catalog entry ^a b c 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 . Vizier catalog entry ^a b Eggen, O. J. (1992). "Asymptotic giant branch stars near the sun".The Astronomical Journal .104 : 275.Bibcode :1992AJ....104..275E .doi :10.1086/116239 . ^a b Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)".VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H .5050 .Bibcode :1995yCat.5050....0H . ^a b Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars".The Journal of the American Association of Variable Star Observers .42 (2): 443.Bibcode :2014JAVSO..42..443M . Vizier catalog entry ^a b Famaey, B.; Pourbaix, D.; Frankowski, A.; Van Eck, S.; Mayor, M.; Udry, S.; Jorissen, A. (2009). "Spectroscopic binaries among Hipparcos M giants".Astronomy and Astrophysics .498 (2): 627.arXiv :0901.0934 Bibcode :2009A&A...498..627F .doi :10.1051/0004-6361/200810698 .S2CID 18739721 . ^a b c Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G.; Valentini, M.; Torralba Elipe, G.; Steinmetz, M.; Pantaleoni-González, M.; Malhotra, S.; Jiménez-Arranz, Ó.; Enke, H.; Casamiquela, L.; Ardèvol, J. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost".Astronomy and Astrophysics .691 : A98.arXiv :2407.06963 Bibcode :2024A&A...691A..98K .doi :10.1051/0004-6361/202451427 . ^a b Brown, A. G. A. ; et al. (Gaia collaboration ) (August 2018)."Gaia Data Release 2: Summary of the contents and survey properties" .Astronomy & Astrophysics 616 . A1.arXiv :1804.09365 Bibcode :2018A&A...616A...1G doi :10.1051/0004-6361/201833051 Gaia DR2 record for this source atVizieR .^a b Lehtinen, Jyri J.; Spada, Federico; Käpylä, Maarit J.; Olspert, Nigul; Käpylä, Petri J. (2020). "Common dynamo scaling in slowly rotating young and evolved stars".Nature Astronomy .4 (7): 658.arXiv :2003.08997 Bibcode :2020NatAs...4..658L .doi :10.1038/s41550-020-1039-x . ^ "2 Peg" .SIMBAD Centre de données astronomiques de Strasbourg . Retrieved2019-04-07 .^ 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 . ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001)."The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog" .The Astronomical Journal .122 (6): 3466.Bibcode :2001AJ....122.3466M .doi :10.1086/323920 Vizier catalog entry ^ Flamsteed, John; Fortin, Jean Nicolas; De Lalande, Joseph Jerome Lefrancais (1795). "Atlas celeste".Paris: Delamarche .Bibcode :1795atce.book.....F .
