Sigma Leonis

Sigma Leonis
Location of σ Leonis (circled in red)
Observation data
Epoch J2000      Equinox ICRS
Constellation Leo
Right ascension 11h 21m 08.1943s
Declination +06° 01′ 45.558″
Apparent magnitude (V) 4.046
Characteristics
Evolutionary stage main sequence
Spectral type B9.5 Vs
U−B color index −0.12
B−V color index −0.06
Astrometry
Radial velocity (Rv)−5.3 km/s
Proper motion (μ) RA: −91.76 mas/yr
Dec.: −12.83 mas/yr
Parallax (π)15.24±0.81 mas
Distance210 ± 10 ly
(66 ± 3 pc)
Absolute magnitude (MV)−0.10
Details
Mass2.76 M☉
Radius3.07±0.23 R☉
Luminosity133 L☉
Surface gravity (log g)3.83±0.03 cgs
Temperature11,000±1,000 K
Metallicity [Fe/H]+0.0 dex
Rotational velocity (v sin i)70 km/s
Age293 Myr
Other designations
σ Leo, 77 Leo, BD+06°2437, FK5 427, HD 98664, HIP 55434, HR 4386, SAO 118804
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. 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, 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. 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.), representing 西上將 (Xīshǎngjiāng), meaning The First Western General. 西上將 (Xīshǎngjiāng), spelled Shang Tseang by R.H. Allen, means "the Higher General".

References

  1. 1 2 3 4 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. 1 2 3 4 5 Perryman, M. A. C.; et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P.
  3. 1 2 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. 1 2 3 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. 1 2 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. 1 2 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. 1 2 3 4 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. 1 2 3 4 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. 1 2 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.