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−B color index
+1.93[ 5]
B−V color 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 (121 ± 3 pc ) Absolute magnitude (MV )−0.89[ 2]
Details Radius 55[ 7] R ☉ Luminosity 653[ 7] L ☉ Temperature 3,919[ 7] K
Other designations 2 Peg ,
NSV 25624,
BD +23°4325,
FK5 1565,
GC 30109,
HD 204724,
HIP 106140,
HR 8225,
SAO 89752,
CCDM J21299+2338A,
WDS J21299+2338A[ 8]
Database references SIMBAD data
2 Pegasi is a single[ 9] star in the constellation Pegasus , located approximately 394 light years away from the Sun based on parallax.[ 1] It is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude of 4.52.[ 2] The object is moving closer to the Earth with a heliocentric radial velocity of −19 km/s.[ 6] It has a magnitude 12.7 visual companion, designated component B, at an angular separation of 30.4″ .[ 10]
This is an aging red giant star with a stellar classification of M1+III,[ 4] currently on the asymptotic giant branch ,[ 3] having exhausted the hydrogen at its core and evolved away from the main sequence . The star has expanded to an estimated 55 times the radius of the Sun .[ 7] It is radiating 653 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,919 K .[ 7]
References
^ 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 d e 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 at VizieR .
^ "2 Peg" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-04-07 .
^ 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