Delta Leonis
Observation data Epoch J2000 Equinox J2000 |
|
---|---|
Constellation | Leo |
Right ascension | 11h 14m 06.50142s[1] |
Declination | 20° 31′ 25.3853″[1] |
Apparent magnitude (V) | 2.56[2] |
Characteristics | |
Spectral type | A4 V[3] |
U−B color index | +0.12[4] |
B−V color index | +0.12[4] |
Variable type | Delta Scuti |
Astrometry | |
Radial velocity (Rv) | -20.2[2] km/s |
Proper motion (μ) | RA: +143.42[1] mas/yr Dec.: -129.88[1] mas/yr |
Parallax (π) | 55.82 ± 0.25[1] mas |
Distance | 58.4 ± 0.3 ly (17.91 ± 0.08 pc) |
Details | |
Mass | 2.2[5] M☉ |
Radius | 2.14 ± 0.040[6] R☉ |
Luminosity | 15.5 ± 1.8[6] L☉ |
Surface gravity (log g) | 3.91[7] cgs |
Temperature | 8,296[6] K |
Rotational velocity (v sin i) | 180[8] km/s |
Age | 0.60-0.75[5] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Delta Leonis (δ Leo, δ Leonis) is a star in the zodiac constellation of Leo. It has the traditional names Zosma (or Zozma) and Duhr. Rare spellings include Zozca, Zosca, Zubra, and Dhur. The name Zosma means girdle in ancient Greek, referring to the star's location in its constellation, on the hip of the lion.[9] Based upon parallax measurements, it lies at a distance of about 58.4 light-years (17.9 parsecs) from the Earth.[1]
Contents
Properties
Zosma is a relatively ordinary main sequence star with a stellar classification of A4 V,[3] making it is somewhat 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 8,296 K,[6] 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 white dwarf.[5]
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.[8]
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.[11] The age of this group is about 500 million years.[12]
Name
In Chinese, 太微右垣 (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.[13] Consequently, δ Leonis itself is known as 太微右垣五 (Tài Wēi Zuǒ Yuán wu, English: the Fifth Star of Right Wall of Supreme Palace Enclosure.),[14] representing 西上相 (Xīshǎngxiāng), meaning The First Western Minister.[15] 西上相 (Xīshǎngxiāng), spelled Shang Seang by R.H. Allen, means "the Higher Minister of State" [16]
See also
References
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- ↑ (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.
- ↑ (Chinese) 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.
- ↑ (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ↑ [1]