Sigma Leonis
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.[2] 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.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Leo |
| Right ascension | 11h 21m 08.1943s[1] |
| Declination | +06° 01′ 45.558″[1] |
| Apparent magnitude (V) | 4.046[2] |
| Characteristics | |
| Spectral type | B9.5 Vs[3] |
| U−B color index | –0.12[4] |
| B−V color index | –0.06[4] |
| Astrometry | |
| Radial velocity (Rv) | –5.3[5] km/s |
| Proper motion (μ) | RA: –91.76[1] mas/yr Dec.: –12.83[1] mas/yr |
| Parallax (π) | 15.24 ± 0.81 mas[1] |
| Distance | 210 ± 10 ly (66 ± 3 pc) |
| Absolute magnitude (MV) | −0.10[6] |
| Details | |
| Mass | 2.76[7] M☉ |
| Radius | 3.3[8] R☉ |
| Luminosity | 133[6] L☉ |
| Surface gravity (log g) | 3.83±0.03[9] cgs |
| Temperature | 10,250[8] K |
| Metallicity [Fe/H] | +0.0[8] dex |
| Rotational velocity (v sin i) | 70[10] km/s |
| Age | 293[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Chini et al. (2012) list this as a single-lined spectroscopic binary system.[3] The visible component has a stellar classification of B9.5 Vs,[3] 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.[12] Sigma Leonis has an estimated 2.76[7] times the mass of the Sun and 3.3[8] times the Sun's radius. It is about 293[7] million years old with a projected rotational velocity of 70 km/s.[10] The star is radiating 133[6] times the Sun's luminosity from its photosphere at an effective temperature of 10,250 K.[8]
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.[13] 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.),[14] representing 西上將 (Xīshǎngjiāng), meaning The First Western General.[15] 西上將 (Xīshǎngjiāng), spelled Shang Tseang by R.H. Allen, means "the Higher General".[16]
References
- ^ 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.
- ^ 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.
- ^ 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
- ^ 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.
- ^ 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.
- ^ a b c 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.
- ^ 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.
- ^ a b c d e 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.
- ^ 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
- ^ 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.
- ^ "sig Leo -- Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-06-23.
- ^ 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.
- ^ (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.
- ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 2010-08-19 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ^ (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name 2008-09-24 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ^ Allen, Richard Hinckley (1963) [1899], "Leo, the Lion", Star Names, Their Lore and Meaning (Dover ed.), retrieved 2017-08-23.