Sigma Pegasi
Star in the constellation Pegasus
σ Pegasi , Latinised as Sigma Pegasi , is a binary star [ 3] system in the northern constellation of Pegasus . With a combined apparent visual magnitude of 5.16,[ 2] it is faintly visible to the naked eye. Based upon an annual parallax shift of 36.66 mas as seen from Earth,[ 1] the system is located 89 light years distant from the Sun . It has a relatively high proper motion , advancing across the celestial sphere at the rate of 0.524 arcseconds per year.[ 11]
The primary, component A, is a yellow-white hued F-type main-sequence star with a stellar classification of F6 V.[ 4] However, Frasca et al. (2009) lists it as a somewhat more evolved F-type subgiant star with a class of F7 IV.[ 5] At the age of 2.7[ 9] billion years, it has an inactive chromosphere [ 4] and is spinning with a leisurely projected rotational velocity of 3 km/s.[ 8] It has a faint, magnitude 13.23[ 12] red dwarf companion, designated component B, at an angular separation of 248 arc seconds .[ 3] The system is most likely (96% chance) a member of the thin disk population of the Milky Way .[ 6]
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 .
^ a b c d Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series , 34 : 1–49, Bibcode :1978A&AS...34....1N .
^ 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 d e f Gray, R. O.; et al. (2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal , 132 (1): 161–70, arXiv :astro-ph/0603770 , Bibcode :2006AJ....132..161G , doi :10.1086/504637 , S2CID 119476992 .
^ a b Frasca, A.; et al. (December 2009), "REM near-IR and optical photometric monitoring of pre-main sequence stars in Orion. Rotation periods and starspot parameters", Astronomy and Astrophysics , 508 (3): 1313–1330, arXiv :0911.0760 , Bibcode :2009A&A...508.1313F , doi :10.1051/0004-6361/200913327 , S2CID 118361131 .
^ a b c Ramírez, I.; et al. (February 2013), "Oxygen abundances in nearby FGK stars and the galactic chemical evolution of the local disk and halo", The Astrophysical Journal , 764 (1): 78, arXiv :1301.1582 , Bibcode :2013ApJ...764...78R , doi :10.1088/0004-637X/764/1/78 , S2CID 118751608 .
^ Karatas, Y.; Schuster, W. J. (October 2006), "Metallicity and absolute magnitude calibrations for UBV photometry", Monthly Notices of the Royal Astronomical Society , 371 (4): 1793–1812, Bibcode :2006MNRAS.371.1793K , doi :10.1111/j.1365-2966.2006.10800.x .
^ a b Takeda, Yoichi; et al. (February 2005), "High-Dispersion Spectra Collection of Nearby F—K Stars at Okayama Astrophysical Observatory: A Basis for Spectroscopic Abundance Standards", Publications of the Astronomical Society of Japan , 57 (1): 13–25, Bibcode :2005PASJ...57...13T , doi :10.1093/pasj/57.1.13 .
^ a b Pace, G. (March 2013), "Chromospheric activity as age indicator. An L-shaped chromospheric-activity versus age diagram", Astronomy & Astrophysics , 551 : 4, arXiv :1301.5651 , Bibcode :2013A&A...551L...8P , doi :10.1051/0004-6361/201220364 , S2CID 56420519 , L8.
^ "49 Peg" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-08-10 .{{cite web }}
: CS1 maint: postscript (link )
^ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal , 129 (3): 1483–1522, arXiv :astro-ph/0412070 , Bibcode :2005AJ....129.1483L , doi :10.1086/427854 , S2CID 2603568 .
^ Lépine, Sébastien; Bongiorno, Bethany (2007), "New Distant Companions to Known Nearby Stars. II. Faint Companions of Hipparcos Stars and the Frequency of Wide Binary Systems", The Astronomical Journal , 133 (3): 889–905, arXiv :astro-ph/0610605 , Bibcode :2007AJ....133..889L , doi :10.1086/510333 , S2CID 16800796 .
External links
Kaler, James B. (November 6, 2015), "Sigma Pegasi" , STARS , University of Illinois, retrieved 2017-08-11 .