Wikipedia

Sigma Pegasi

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]

Sigma Pegasi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pegasus
Right ascension 22h 52m 24.07496s[1]
Declination 09° 50′ 08.3791″[1]
Apparent magnitude (V) 5.16[2] 13.5[3]
Characteristics
Spectral type F6 V[4] or F7 IV[5] M4 V[3]
U−B color index −0.016[2]
B−V color index 0.486[2]
Astrometry
Radial velocity (Rv) 11.4[6] km/s
Proper motion (μ) RA:  521.04[1] mas/yr
Dec.:  42.65[1] mas/yr
Parallax (π)36.66 ± 0.29 mas[1]
Distance89.0 ± 0.7 ly
(27.3 ± 0.2 pc)
Absolute magnitude (MV)3.01[7]
Details
σ Peg A
Mass1.275[6] M☉
Surface gravity (log g)3.69[4] cgs
Temperature6,250[4] K
Metallicity [Fe/H]−0.32[4] dex
Rotational velocity (v sin i)3[8] km/s
Age2.71±0.61[9] Gyr
Other designations
σ Peg, 49 Peg, BD 09° 5122, FK5 3828, HD 216385, HIP 112935, HR 8697, SAO 127810[10]
Database references
SIMBADdata

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

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  1. ^ 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 18759600.653-664&rft.date=2007&rft_id=info:arxiv/0708.1752&rft_id=https://api.semanticscholar.org/CorpusID:18759600#id-name=S2CID&rft_id=info:doi/10.1051/0004-6361:20078357&rft_id=info:bibcode/2007A&A...474..653V&rft.aulast=van Leeuwen&rft.aufirst=F.&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
  2. ^ 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.1-49&rft.date=1978&rft_id=info:bibcode/1978A&AS...34....1N&rft.aulast=Nicolet&rft.aufirst=B.&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
  3. ^ 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 14878976.869-879&rft.date=2008-09&rft_id=info:arxiv/0806.2878&rft_id=https://api.semanticscholar.org/CorpusID:14878976#id-name=S2CID&rft_id=info:doi/10.1111/j.1365-2966.2008.13596.x&rft_id=info:bibcode/2008MNRAS.389..869E&rft.aulast=Eggleton&rft.aufirst=P. P.&rft.au=Tokovinin, A. A.&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
  4. ^ 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 119476992.161-70&rft.date=2006&rft_id=info:arxiv/astro-ph/0603770&rft_id=https://api.semanticscholar.org/CorpusID:119476992#id-name=S2CID&rft_id=info:doi/10.1086/504637&rft_id=info:bibcode/2006AJ....132..161G&rft.aulast=Gray&rft.aufirst=R. O.&rft.au=Corbally, C. J.&rft.au=Garrison, R. F.&rft.au=McFadden, M. T.&rft.au=Bubar, E. J.&rft.au=McGahee, C. E.&rft.au=O'Donoghue, A. A.&rft.au=Knox, E. R.&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
  5. ^ 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 118361131.1313-1330&rft.date=2009-12&rft_id=info:arxiv/0911.0760&rft_id=https://api.semanticscholar.org/CorpusID:118361131#id-name=S2CID&rft_id=info:doi/10.1051/0004-6361/200913327&rft_id=info:bibcode/2009A&A...508.1313F&rft.aulast=Frasca&rft.aufirst=A.&rft.au=Covino, E.&rft.au=Spezzi, L.&rft.au=Alcalá, J. M.&rft.au=Marilli, E.&rft.au=Fżrész, G.&rft.au=Gandolfi, D.&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
  6. ^ 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.
  7. ^ 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.1793-1812&rft.date=2006-10&rft_id=info:doi/10.1111/j.1365-2966.2006.10800.x&rft_id=info:bibcode/2006MNRAS.371.1793K&rft.aulast=Karatas&rft.aufirst=Y.&rft.au=Schuster, W. J.&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
  8. ^ 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/57.1.13.13-25&rft.date=2005-02&rft_id=info:doi/10.1093/pasj/57.1.13&rft_id=info:bibcode/2005PASJ...57...13T&rft.aulast=Takeda&rft.aufirst=Yoichi&rft.au=Sato, Bun'ei&rft.au=Kambe, Eiji&rft.au=Masuda, Seiji&rft.au=Izumiura, Hideyuki&rft.au=Watanabe, Etsuji&rft.au=Ohkubo, Michiko&rft.au=Yanagisawa, Kenshi&rft.au=Yasaka, Yoshiro&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
  9. ^ 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.
  10. ^ "49 Peg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-10.{{cite web}}: CS1 maint: postscript (link)
  11. ^ 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 2603568.1483-1522&rft.date=2005-03&rft_id=info:arxiv/astro-ph/0412070&rft_id=https://api.semanticscholar.org/CorpusID:2603568#id-name=S2CID&rft_id=info:doi/10.1086/427854&rft_id=info:bibcode/2005AJ....129.1483L&rft.aulast=Lépine&rft.aufirst=Sébastien&rft.au=Shara, Michael M.&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
  12. ^ 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 16800796.889-905&rft.date=2007&rft_id=info:arxiv/astro-ph/0610605&rft_id=https://api.semanticscholar.org/CorpusID:16800796#id-name=S2CID&rft_id=info:doi/10.1086/510333&rft_id=info:bibcode/2007AJ....133..889L&rft.aulast=Lépine&rft.aufirst=Sébastien&rft.au=Bongiorno, Bethany&rfr_id=info:sid/en.wikipedia.org:Sigma Pegasi" class="Z3988">
edit
  • Kaler, James B. (November 6, 2015), "Sigma Pegasi", STARS, University of Illinois, retrieved 2017-08-11.
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