| absmag_v = −1.41[13]
}}{{Starbox detail
| mass = 2.1[14]
| radius = 95
| luminosity =
| temperature = 3,689[15]
| gravity = 1.20[15]
| metal_fe = –0.11[15]
| rotational_velocity = 9.7[18]
| age =
}}{{Starbox catalog
| names = Scheat, 53 Peg, HR 8775, BD +27°4480, HD 217906, SAO 90981, FK5 870, HIP 113881.[5]
}}{{Starbox reference
| Simbad=HD+217906
}}{{Starbox end}}Beta Pegasi (β Pegasi, abbreviated Beta Peg, β Peg), also named Scheat,[1] is a red giant star and the second-brightest star (after Epsilon Pegasi) in the constellation of Pegasus. It forms the upper right corner of the Great Square of Pegasus,[21] a prominent rectangular asterism.
Nomenclature
β Pegasi (Latinised to Beta Pegasi) is the star's Bayer designation.
It bore the traditional name of Scheat, a name that had also been used for Delta Aquarii. The name was derived from the Arabic Al Sā'id "the upper arm", or from Sa'd.[21] In 2016, the International Astronomical Union organised a Working Group on Star Names (WGSN)[2] to catalog and standardise proper names for stars. The WGSN's first bulletin of July 2016[3] included a table of the first two batches of names approved by the WGSN; which included Scheat for this star (the name Skat was later approved for Delta Aquarii[1]).
Arabian astronomers named it Mankib al Faras, meaning the "Horse's shoulder"{{Citation needed|date=December 2017}}.
In Chinese, {{lang|zh|室宿}} ({{lang|zh-Latn|Shì Xiù}}), meaning Encampment, refers to an asterism consisting β Pegasi and α Pegasi.[4] Consequently, β Pegasi itself is known as {{lang|zh|室宿二}} ({{lang|zh-Latn|Shì Xiù èr}}), "the Second Star of Encampment".[5]
Distance and properties
Based upon parallax measurements, Beta Pegasi is located about {{Convert|196|ly|pc|abbr=off|lk=on}} from the Sun.[ It is unusual among bright stars in having a relatively cool surface temperature compared to stars like the Sun.]
This star has a stellar classification of M2.3 II–III,[5] which indicates the spectrum has characteristics partway between a bright giant and a giant star. It has expanded until it is some 95 times as large, and has a total luminosity of 1,500 times that of the Sun. The effective temperature of the star's outer envelope is about 3,700 K,[15] giving the star the characteristic orange-red hue of an M-type star.[31] The photosphere is sufficiently cool for molecules of titanium oxide to form.[32]
Beta Pegasi is a semi-regular variable with a period of 43.3 days[8] and a brightness that varies from magnitude +2.31 to +2.74 (averaging 2.42).[4] It is losing mass at a rate at or below 10−8 times the Sun's mass per year, which is creating an expanding shell of gas and dust with a radius of about 3,500 times the Sun's radius (16 astronomical units).[35]
References
1. ^1 {{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names |accessdate=28 July 2016}}
2. ^{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|accessdate=22 May 2016}}
3. ^{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 |accessdate=28 July 2016}}
4. ^{{zh icon}} 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}.
5. ^{{zh icon}} 香港太空館 - 研究資源 - 亮星中英對照表 {{webarchive|url=https://web.archive.org/web/20081025110153/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm |date=2008-10-25 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.
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7. ^1 {{citation | last=Wilson | first=Ralph Elmer | date=1953 | title=General Catalogue of Stellar Radial Velocities | journal=Washington | publisher=Carnegie Institution of Washington | location=Washington | bibcode=1953GCRV..C......0W }}
8. ^1 {{citation | display-authors=1 | last1=Massarotti | first1=Alessandro | last2=Latham | first2=David W. | last3=Stefanik | first3=Robert P. | last4=Fogel | first4=Jeffrey | title=Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity | journal=The Astronomical Journal | volume=135 | issue=1 | pages=209–231 |date=January 2008 | doi=10.1088/0004-6256/135/1/209 | bibcode=2008AJ....135..209M }}
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10. ^1 2 3 {{citation | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+217906 | title =V* bet Peg -- Pulsating variable Star | publisher=Centre de Données astronomiques de Strasbourg | work=SIMBAD | accessdate=2010-01-05 }}
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12. ^1 2 {{citation | title=Query= bet Peg | url=http://www.sai.msu.su/gcvs/cgi-bin/search.cgi?search=bet+Peg | publisher=Centre de Données astronomiques de Strasbourg | work=General Catalogue of Variable Stars | accessdate=2010-01-05}}
13. ^1 2 {{citation | last1=Allen | first1=Richard Hinckley | date=1899 | title=Star Names: Their Lore and Meaning | publisher=Dover Publications Inc. | location=New York, NY | isbn=0-486-21079-0 | page=325 | authorlink=Richard Hinckley Allen | url=https://books.google.com/books?id=5xQuAAAAIAAJ&pg=PA325 }}
14. ^1 {{citation | last1=Mauron | first1=N. | last2=Caux | first2=E. | title=K I/Na I scattering observations in circumstellar envelopes - Alpha(1) Herculis, Omicron Ceti, TX PISCIUM and Beta Pegasi | journal=Astronomy and Astrophysics | volume=265 | issue=2 | pages=711–725 |date=November 1992 | bibcode=1992A&A...265..711M }}. Solar Radius = 0.0046491 AU.
15. ^1 {{citation | last1=Gavin | first1=M. | title=Stellar spectroscopy with CCDs - some preliminary results | journal=Journal of the British Astronomical Association | volume=106 | issue=1 | pages=11–15 |date=February 1996 | bibcode=1996JBAA..106...11G }}
16. ^1 {{citation |title=The Colour of Stars |date=December 21, 2004 |work=Australia Telescope, Outreach and Education |publisher=Commonwealth Scientific and Industrial Research Organisation |url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |accessdate=2012-01-16 |deadurl=yes |archiveurl=https://www.webcitation.org/6630AbtJZ?url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |archivedate=2012-03-10 |df= }}
17. ^1 {{cite conference | last1=Tsuji | first1=Takashi | contribution=Isotopic abundances of Carbon and Oxygen in Oxygen-rich giant stars | title=Convection in Astrophysics, Proceedings of IAU Symposium #239 held 21-25 August, 2006 in Prague, Czech Republic | journal=Proceedings of the International Astronomical Union | volume=2 | editor1-first=F. | editor1-last=Kupka | editor2-first=I. | editor2-last=Roxburgh | editor3-first=K. | editor3-last=Chan | pages=307–310 |date=May 2007 | doi=10.1017/S1743921307000622 | bibcode=2007IAUS..239..307T |arxiv = astro-ph/0610180 }}
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