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Sigma Leonis

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Sigma Leonis
Observation data
Epoch J2000      Equinox J2000
Constellation Leo[1]
Right ascension 11h 21m 08.1943s[2]
Declination +06° 01′ 45.558″[2]
Apparent magnitude (V) 4.046[3]
Characteristics
Evolutionary stage main sequence[4]
Spectral type B9.5 Vs[5]
U−B color index −0.12[6]
B−V color index −0.06[6]
Astrometry
Radial velocity (Rv)−5.3[7] km/s
Proper motion (μ) RA: −91.76[2] mas/yr
Dec.: −12.83[2] mas/yr
Parallax (π)15.24±0.81 mas[2]
Distance210 ± 10 ly
(66 ± 3 pc)
Absolute magnitude (MV)−0.10[1]
Details
Mass2.76[8] M☉
Radius3.07±0.23[9] R☉
Luminosity133[1] L☉
Surface gravity (log g)3.83±0.03[10] cgs
Temperature11,000±1,000[9] K
Metallicity [Fe/H]+0.0[11] dex
Rotational velocity (v sin i)70[12] km/s
Age293[8] Myr
Other designations
σ Leo, 77 Leo, BD−06°2437, FK5 427, HD 98664, HIP 55434, HR 4386, SAO 118804[13]
Database references
SIMBADdata

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.[3] 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.[7]

Chini et al. (2012) list this as a single-lined spectroscopic binary system.[5] The visible component has a stellar classification of B9.5 Vs,[5] 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.[14] Sigma Leonis has an estimated 2.76 times the mass of the Sun[8] and 3.07 times the Sun's radius.[9] It is about 293 million years old[8] with a projected rotational velocity of 70 km/s.[12] The star is radiating 133 times the Sun's luminosity from its photosphere[1] at an effective temperature of 11,000 K.[9]

Name

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In Chinese, 太微右垣 (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.[15] Consequently, the Chinese name for σ Leonis itself is 太微右垣二 (Tài Wēi Yòu Yuán èr, English: the Second Star of Right Wall of Supreme Palace Enclosure.),[16] representing 西上將 (Xīshǎngjiāng), meaning The First Western General.[17] 西上將 (Xīshǎngjiāng), spelled Shang Tseang by R.H. Allen, means "the Higher General".[18]

References

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  1. ^ a b c d Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  2. ^ a b c d e Perryman, M. A. C.; et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics. 323: L49 – L52. Bibcode:1997A&A...323L..49P.
  3. ^ a b Cousins, A. W. J. (1984). "Standardisation of broad band photometry of equatorial standards". South Africa Astronomical Observatory Circular. 8: 59–67. Bibcode:1984SAAOC...8...59C.
  4. ^ Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  5. ^ a b c Chini, R.; et al. (August 2012). "spectroscopic survey on the multiplicity of high-mass stars". Monthly Notices of the Royal Astronomical Society. 424 (3): 1925–1929. arXiv:1205.5238. Bibcode:2012MNRAS.424.1925C. doi:10.1111/j.1365-2966.2012.21317.x. S2CID 119120749.
  6. ^ a b Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
  7. ^ a b Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  8. ^ a b c d David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607.
  9. ^ a b c d Gordon, Kathryn D.; Gies, Douglas R.; Schaefer, Gail H.; Huber, Daniel; Ireland, Michael (2019). "Angular Sizes, Radii, and Effective Temperatures of B-type Stars from Optical Interferometry with the CHARA Array". The Astrophysical Journal. 873 (1): 91. Bibcode:2019ApJ...873...91G. doi:10.3847/1538-4357/ab04b2. S2CID 125181833.
  10. ^ Fitzpatrick, E. L.; Massa, D. (March 2005). "Determining the Physical Properties of the B Stars. II. Calibration of Synthetic Photometry". The Astronomical Journal. 129 (3): 1642–1662. arXiv:astro-ph/0412542. Bibcode:2005AJ....129.1642F. doi:10.1086/427855. S2CID 119512018.
  11. ^ Lipski, Ł.; Stȩpień, K. (March 2008). "Effective temperatures of magnetic chemically peculiar stars from full spectral energy distributions". Monthly Notices of the Royal Astronomical Society. 385 (1): 481–492. arXiv:0712.3664. Bibcode:2008MNRAS.385..481L. doi:10.1111/j.1365-2966.2008.12856.x. S2CID 118320684.
  12. ^ a b Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1): 1. Bibcode:1970CoAsi.239....1B.
  13. ^ "sig Leo -- Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-06-23.
  14. ^ Wraight, K. T.; et al. (February 2012). "A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars". Monthly Notices of the Royal Astronomical Society. 420 (1): 757–772. arXiv:1110.6283. Bibcode:2012MNRAS.420..757W. doi:10.1111/j.1365-2966.2011.20090.x. S2CID 14811051.
  15. ^ (in Chinese) 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.
  16. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2010-08-19 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  17. ^ (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived 2008-09-24 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  18. ^ Allen, Richard Hinckley (1963) [1899]. "Leo, the Lion". Star Names, Their Lore and Meaning (Dover ed.). Retrieved 2017-08-23.
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