Sigma Pegasi – Wikipedia

	Sigma Pegasi (σ)
Observationsdata; Epok: J2000.0
Stjärnbild	Pegasus
Rektascension	22t 52m 24,07496s
Deklination	09° 50′ 08,3791″
Skenbar magnitud ()	+5,16 + 13,5
Stjärntyp
Spektraltyp	F6 V eller F7 IV + M4 V
U–B	-0,016
B–V	+0,486
Astrometri
Radialhastighet ()	+11,4 km/s
Egenrörelse (µ)	RA: +521,04 mas/år; Dek.: +42,65 mas/år
Parallax ()	36,66 ± 0,29
Avstånd	89,0 ± 0,7 lå (27,3 ± 0,2 pc)
Absolut magnitud ()	3,01
Detaljer
Massa	1,275 M☉
Radie	1,94 R☉
Luminositet	5,51 L☉
Temperatur	6 250 K
Metallicitet	-0,32 dex
Vinkelhastighet	3 km/s
Ålder	2,71 ± 0,61 miljarder år
Andra beteckningar
	σ Peg, 49 Pegasi, BD+09° 5122, FK5 3828, HD 216385, HIP 112935, HR 8697, SAO 127810

Sigma Pegasi (σ Pegasi, förkortat Sigma Peg, σ Peg) som är stjärnans Bayerbeteckning, är en dubbelstjärna^[3] belägen i den södra delen av stjärnbilden Pegasus. Den har en skenbar magnitud på 5,16^[2] och är synlig för blotta ögat där ljusföroreningar ej förekommer. Baserat på parallaxmätning inom Hipparcosuppdraget på ca 36,7^[1] mas, beräknas den befinna sig på ett avstånd på ca 89 ljusår (ca 27 parsek) från solen. Den har en relativt snabb rörelse genom rymden och förflyttar sig med en hastighet av 0,524 bågsekunder per år.^[12]

Egenskaper

Primärstjärnan Sigma Pegasi A är en gul till vit stjärna i huvudserien av spektralklass F6 V^[4] eller F7 IV^[5]. Den har en massa som är knappt 30 procent^[6] större än solens massa, en radie som är knappt dubbelt^[8] så stor som solens och utsänder från dess fotosfär ca 5,5^[8] gånger mera energi än solen vid en effektiv temperatur på ca 6 250^[4] K.

Följeslagaren Sigma Pegasi B är en svag röd dvärgstjärna av magnitud 13,23^[13], separerad med 248 bågsekunder.^[3] Stjärnparet befinner sig med 96 procent sannolikhet i Vintergatans tunna skiva.^[6]

Referenser

Den här artikeln är helt eller delvis baserad på material från engelskspråkiga Wikipedia, tidigare version.

Noter

^ [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.
^ [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.
^ [a b c d e] 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.
^ [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.
^ [a b c d] 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.
^ 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 c d] https://www.universeguide.com/star/sigmapegasi . Hämtad 2018-08-05.
^ 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.
^ 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, L8.
^ "49 Peg". SIMBAD. Centre de données astronomiques de Strasbourg. Hämtad 2017-08-10.
^ 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.
^ 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.

Externa länkar

https://www.universeguide.com/star/sigmapegasi
stars.astro.illinois.edu/sow/sigmapeg.html

[A-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.

[B-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

[C-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.

[D-4] [a b c d e] 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.

[E-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.

[F-6] [a b c d] 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.

[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.

[G-8] [a b c d] https://www.universeguide.com/star/sigmapegasi . Hämtad 2018-08-05.

[9] 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.

[10] 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, L8.

[11] "49 Peg". SIMBAD. Centre de données astronomiques de Strasbourg. Hämtad 2017-08-10.

[12] 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.

[13] 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.

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