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, (), meaning Right Wall of Supreme Palace Enclosure, refers to an asterism consisting of σ Leonis, β Virginis, ι Leonis, θ Leonis and δ Leonis. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, . Consequently, the Chinese name for σ Leonis itself is (, .), 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010. representing (), meaning The First Western General. English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name , 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".
References