delta Leonis

δ Leonis is a main-sequence star with a stellar classification of A4 V, meaning it is larger and hotter than the Sun. It is a fairly well-studied star, allowing relatively accurate measurements of its age and size. The radius of the star, as measured directly using an interferometer, is about 214% of the Sun's radius and it is emitting more than 15 times as much luminosity as the Sun. The energy is being emitted from the outer envelope with an effective temperature {{val|8296|ul=K|fmt=commas}}, giving it the white hue characteristic of an A-type star. Having a larger mass than the Sun it will have a shorter lifespan, and in another 600 million years or so will swell into an orange or red giant star before decaying quietly into a remnant white dwarf consisting of carbon and oxygen.

This star is rotating rapidly, with a projected rotational velocity of 180 km s⁻¹. The inclination of the axis of rotation to the line of sight from the Earth is estimated at 38.1°, which would mean the azimuthal velocity along the equator is about 280 km s⁻¹. This rotation is producing an equatorial bulge, giving the star a pronounced oblate spheroidal shape. The polar radius is about 84% of the radius along the equator.

Based upon the location and trajectory of this star through space, it may be a member of the Ursa Major Moving Group, a type of stellar kinematics group that share a common origin and motion through space. The age of this group is about 500 million years.

δ Leonis (Latinised to Delta Leonis) is the star's Bayer designation.

It bore the traditional names Zosma or Zozma and Duhr (rare spellings included Zozca, Zosca, Al-Zubra الزبرة, traditional Arabic for both shoulder, and a lion's mane and Dhur ظهر, the latter meaning 'back' in Arabic{{citation needed|date=April 2017}}). Zosma means 'girdle' in ancient Greek, referring to the star's location in its constellation, on the hip of the lion. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN){{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|access-date=22 May 2016}} to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 |access-date=28 July 2016}} included a table of the first two batches of names approved by the WGSN, which included Zosma for this star.

In Chinese, {{lang|zh|太微右垣}} ({{lang|zh-Latn|Tài Wēi Yòu Yuán}}), meaning Right Wall of Supreme Palace Enclosure, refers to an asterism consisting of δ Leonis, β Virginis, σ Leonis, ι Leonis and θ Leonis.{{in lang|zh}} 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}}. Consequently, the Chinese name for δ Leonis itself is {{lang|zh|太微右垣五}} ({{lang|zh-Latn|Tài Wēi Zuǒ Yuán wu}}, {{langx|en|the Fifth Star of Right Wall of Supreme Palace Enclosure}}),{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_t_z.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive |url=https://web.archive.org/web/20100819122914/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_t_z.htm |date=August 19, 2010 }}, Hong Kong Space Museum. Accessed on line November 23, 2010. representing {{lang|zh|西上相}} ({{lang|zh-Latn|Xīshǎngxiāng}}), meaning The First Western Minister.{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#SupremePalaceEnclosure English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name] {{webarchive |url=https://web.archive.org/web/20100810114313/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#SupremePalaceEnclosure |date=August 10, 2010 }}, Hong Kong Space Museum. Accessed on line November 23, 2010. 西上相 (Xīshǎngxiāng), spelled Shang Seang by R.H. Allen, means "the Higher Minister of State".

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{{Stars of Leo}}

{{DEFAULTSORT:Delta Leonis}}

Category:A-type main-sequence stars

Category:Ursa Major moving group

Zosma

Leonis, Delta

Category:Leo (constellation)

Category:Durchmusterung objects

Leonis, 68

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