Sigma Leonis
{{Short description|Star in the constellation Leo}}
{{Starbox begin
| name=Sigma Leonis
}}
{{Starbox observe
| epoch=J2000
| constell=Leo
}}
{{Starbox character
| type = main sequence
| variable=
}}
{{Starbox astrometry
| parallax=15.24
| p_error=0.81
}}
{{Starbox detail
| temperature={{val|11000|1000|fmt=commas}}
| rotation=
}}
{{Starbox catalog
| names = {{odlist | B=σ Leo | F=77 Leo | BD=−06°2437 | FK5=427 | HD=98664 | HIP=55434 | HR=4386 | SAO=118804 | GC=| LHS=}}{{cite web | title=sig Leo -- Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Sigma+Leonis | accessdate=2010-06-23 }}
}}
{{Starbox reference
|Simbad=sig+Leo
}}
{{Starbox end}}
Sigma Leonis, Latinized from σ Leonis, is a blue-white hued star in the zodiac constellation Leo that is visible to the naked eye with an apparent visual magnitude of 4.0. Its annual parallax shift of 15.24 mas as seen from Earth implies a distance around 210 light years from the Sun. It is moving closer to the Sun with a radial velocity of –5 km/s.
Chini et al. (2012) list this as a single-lined spectroscopic binary system. The visible component has a stellar classification of B9.5 Vs, indicating it is a B-type main-sequence star. It is a suspected magnetic Ap star that shows an abundance anomaly with the element silicon. Sigma Leonis has an estimated 2.76 times the mass of the Sun and 3.07 times the Sun's radius. It is about 293 million years old with a projected rotational velocity of 70 km/s. The star is radiating 133 times the Sun's luminosity from its photosphere at an effective temperature of 11,000 K.
Name
In Chinese, {{lang|zh|太微右垣}} ({{lang|zh-Latn|Tài Wēi Yòu Yuán}}), meaning Right Wall of Supreme Palace Enclosure, refers to an asterism consisting of σ Leonis, β Virginis, ι Leonis, θ Leonis and δ Leonis.{{in lang|zh}} 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}}. Consequently, the Chinese name for σ Leonis itself is {{lang|zh|太微右垣二}} ({{lang|zh-Latn|Tài Wēi Yòu Yuán èr}}, {{langx|en|the Second Star of Right Wall of Supreme Palace Enclosure}}.),{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_t_z.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive|url=https://web.archive.org/web/20100819122914/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_t_z.htm |date=2010-08-19 }}, Hong Kong Space Museum. Accessed on line November 23, 2010. representing {{lang|zh|西上將}} ({{lang|zh-Latn|Xīshǎngjiāng}}), meaning The First Western General.{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#SupremePalaceEnclosure English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name] {{webarchive|url=https://web.archive.org/web/20080924022136/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm |date=2008-09-24 }}, Hong Kong Space Museum. Accessed on line November 23, 2010. 西上將 (Xīshǎngjiāng), spelled Shang Tseang by R.H. Allen, means "the Higher General".{{cite book
| first1=Richard Hinckley | last1=Allen
| orig-year=1899 | year=1963 | edition=Dover
| title=Star Names, Their Lore and Meaning | chapter=Leo, the Lion
| chapter-url=https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Leo*.html
| accessdate=2017-08-23 }}
References
{{reflist|refs=
| title=Standardisation of broad band photometry of equatorial standards
| journal=South Africa Astronomical Observatory Circular
| volume=8 | pages=59–67 | year=1984
| bibcode=1984SAAOC...8...59C
| last1=Cousins | first1=A. W. J. }}
| title=A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars
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| last3=Netopil | first3=M. | last4=Paunzen | first4=E.
| last5=Rode-Paunzen | first5=M. | last6=Bewsher | first6=D.
| last7=Norton | first7=A. J. | last8=White | first8=Glenn J.
| display-authors=1
| journal=Monthly Notices of the Royal Astronomical Society
| volume=420 | issue=1 | pages=757–772 | date=February 2012
| doi=10.1111/j.1365-2966.2011.20090.x | doi-access=free | bibcode=2012MNRAS.420..757W |arxiv = 1110.6283 | s2cid=14811051 }}
| title=spectroscopic survey on the multiplicity of high-mass stars
| display-authors=1 | last1=Chini | first1=R.
| last2=Hoffmeister | first2=V. H. | last3=Nasseri | first3=A.
| last4=Stahl | first4=O. | last5=Zinnecker | first5=H.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=424 | issue=3 | pages=1925–1929 | date=August 2012
| doi=10.1111/j.1365-2966.2012.21317.x | doi-access=free | bibcode=2012MNRAS.424.1925C | arxiv=1205.5238| s2cid=119120749 }}
| title=XHIP: An extended hipparcos compilation
| last1=Anderson | first1=E. | last2=Francis | first2=Ch.
| journal=Astronomy Letters
| volume=38 | issue=5 | pages=331 | year=2012
| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015
| arxiv=1108.4971 | s2cid=119257644 }}
| title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets
| last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A.
| journal=The Astrophysical Journal
| volume=804 | issue=2 | pages=146 | year=2015
| bibcode=2015ApJ...804..146D | doi=10.1088/0004-637X/804/2/146
| arxiv=1501.03154 | s2cid=33401607 }}
{{cite journal | author=Lipski, Ł.| author2=Stȩpień, K. | title=Effective temperatures of magnetic chemically peculiar stars from full spectral energy distributions | journal=Monthly Notices of the Royal Astronomical Society | volume=385 | issue=1 | pages=481–492 |date=March 2008 | doi=10.1111/j.1365-2966.2008.12856.x | doi-access=free | bibcode=2008MNRAS.385..481L |arxiv = 0712.3664 | s2cid=118320684 }}
}}
{{Stars of Leo}}
{{DEFAULTSORT:Sigma Leonis}}
Category:B-type main-sequence stars