Zeta Draconis
 Location of ζ Draconis (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Draco |
| Right ascension | 17h 08m 47.19596s[1] |
| Declination | +65° 42′ 52.8634″[1] |
| Apparent magnitude (V) | +3.17[2] |
| Characteristics | |
| Spectral type | B6 III[3] |
| U−B color index | –0.43[2] |
| B−V color index | –0.11[2] |
| Astrometry | |
| Radial velocity (Rv) | –17[4] km/s |
| Proper motion (μ) | RA: –20.43[1] mas/yr Dec.: +19.61[1] mas/yr |
| Parallax (π) | 9.93 ± 0.35[1] mas |
| Distance | 330 ± 10 ly (101 ± 4 pc) |
| Details | |
| Mass | 3.5[5] M☉ |
| Radius | 2.3[5] R☉ |
| Luminosity | 148[5] L☉ |
| Surface gravity (log g) | 4.24[3] cgs |
| Temperature | 13,397[3] K |
| Metallicity [Fe/H] | –0.95[3] dex |
| Rotational velocity (v sin i) | 55[6] km/s |
| Other designations | |
Zeta Draconis (ζ Dra, ζ Draconis) is the Bayer designation for a star in the northern circumpolar constellation of Draco. It shares the Arabic name Al dhi'bah ('the hyenas') with several other stars in the constellation,[8] and shares the name Al dhibain with Eta Draconis.[9] It is known as Nodus III (Third Knot, the knot being a loop in the tail of Draco).[10] With an apparent visual magnitude of +3.17,[2] it is the fifth brightest member of this generally faint constellation. The distance to Zeta Draconis has been measured using the parallax technique, yielding an estimate of roughly 330 light-years (100 parsecs) away.[1]
In Chinese, 紫微左垣 (Zǐ Wēi Zuǒ Yuán), meaning Left Wall of Purple Forbidden Enclosure, refers to an asterism consisting of ζ Draconis, ι Draconis, η Draconis, θ Draconis, υ Draconis, 73 Draconis, γ Cephei and 23 Cassiopeiae.[11] Consequently, ζ Draconis itself is known as 紫微左垣四 (Zǐ Wēi Zuǒ Yuán sì, English: the Fourth Star of Left Wall of Purple Forbidden Enclosure.),[12] representing 上弼 (Shǎngbì), meaning The First Minister.[13] 上弼 (Shǎngbì) is westernized into Shang Pih by R.H. Allen with meaning "the Higher Minister".[14]
Zeta Draconis is a giant star with a stellar classification of B6 III.[3] Compared to the Sun, this star is about 2.5 times larger, 3.5 times more massive, and is radiating 148 times as much luminosity.[5] This energy is being emitted from the star's outer envelope at an effective temperature of nearly 13,400 K.[3] The azimuthal rotation velocity along the equator is at least 55 km/s.[6]
The north ecliptic pole is located at right ascension 18h and declination +66.5°.[15] This is located roughly mid-way between Delta Draconis and Zeta Draconis.[16]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 5.0 5.1 5.2 5.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 6.0 6.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ (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) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日
- ↑ (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ↑ Star Name - R.H. Allen p. 210
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
