Theta Leonis, Latinized from θ Leonis, formally named Chertan,[ it is visible to the naked eye and forms one of the brighter stars in the constellation. The distance from the Sun can be directly determined from parallax measurements, yielding a value of about .][
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Description
This is a large star with 2.8 times the mass of the Sun and four times the Sun's radius.[ The stellar spectrum matches a stellar classification of A2 V,][ making this a seemingly typical A-type main sequence star. However, the spectrum shows enhanced absorption lines of metals, marking this as a chemically peculiar Am star.][ The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, appears around 12% higher than in the Sun.][ It is radiating 118 times the luminosity of the Sun from its outer atmosphere at an effective temperature of 9,480 K,][ literally giving it a white-hot glow.][
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Theta Leonis is much younger than the Sun, with an estimated age of around 550 million years.[ It has a moderately high rate of rotation, with a projected rotational velocity of .][ However, interferometric observations suggest that it is a rapidly rotating star being viewed nearly pole-on.][ Measurements in the infrared band show an infrared excess from the star and its surroundings, suggesting the presence of a circumstellar disk of dust. The temperature of this emission indicates the disk has an orbital radius of 36 AU.][
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Nomenclature
θ Leonis (Latinised to Theta Leonis) is the star's Bayer designation.
It bore the traditional names Chertan, Chort [ Chertan is derived from the Arabic 'two small ribs', originally referring to Delta Leonis and Theta Leonis; Chort from Arabic or 'small rib', and Coxa is Latin for 'hip'. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)]
In Chinese, 太微右垣 (Tài Wēi Yòu Yuán), meaning Right Wall of Supreme Palace Enclosure, refers to an asterism consisting of Theta Leonis, Beta Virginis, Sigma Leonis, Iota Leonis and Delta 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 Theta Leonis itself is 太微右垣四 (Tài Wēi Zuǒ Yuán sì, .),[ 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 西次相 (Xīcìxiāng), meaning The Second Western Minister.[ English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name , Hong Kong Space Museum. Accessed on line November 23, 2010.] 西次相 (Xīcìxiāng), spelled Tsze Seang by R.H. Allen, means "the Second Minister of State"
