Zeta Draconis

Zeta Draconis
Diagram showing star positions and boundaries of the Draco constellation and its surroundings


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
Distance330 ± 10 ly
(101 ± 4 pc)
Details
Mass3.5[5] M☉
Radius2.3[5] R☉
Luminosity148[5] L☉
Surface gravity (log g)4.24[3] cgs
Temperature13,397[3] K
Metallicity [Fe/H]–0.95[3] dex
Rotational velocity (v sin i)55[6] km/s
Other designations
22 Draconis, BD+65 1170, FK5 639, HD 155763, HIP 83895, HR 6396, SAO 17365.[7]

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 midway between Delta Draconis and Zeta Draconis.[16]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 1 2 3 4 Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J.
  3. 1 2 3 4 5 6 Cenarro, A. J.; et al. (2007), "Medium-resolution Isaac Newton Telescope Library of Empirical Spectra – II. The Stellar Atmospheric Parameters", Monthly Notices of the Royal Astronomical Society, 374 (2): 664–690, arXiv:astro-ph/0611618Freely accessible, Bibcode:2007MNRAS.374..664C, doi:10.1111/j.1365-2966.2006.11196.x.
  4. ↑ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E.
  5. 1 2 3 4 Malagnini, M. L.; Morossi, C. (November 1990), "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars", Astronomy and Astrophysics Supplement Series, 85 (3): 1015–1019, Bibcode:1990A&AS...85.1015M.
  6. 1 2 Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897–911, arXiv:astro-ph/0205255Freely accessible, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943.
  7. ↑ "Zet Dra", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2009-10-10.
  8. ↑ Allen, Richard Hinckley (1899), Star-names and their meanings, New York: G. E. Stechert, p. 210.
  9. ↑ Rumrill, H. B. (June 1936), "Star Name Pronunciation", Publications of the Astronomical Society of the Pacific, 48 (283): 139–154, Bibcode:1936PASP...48..139R, doi:10.1086/124681.
  10. ↑ Kaler, Jim, "Al Dhibain ("The Posterior")", Stars, University of Illinois, retrieved 2009-10-12.
  11. ↑ (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.
  12. ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日
  13. ↑ (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived August 10, 2010, at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.
  14. ↑ Star Name - R.H. Allen p. 210
  15. ↑ Chartrand, Mark R.; Wimmer, Helmut K. (2001), Night Sky: A Guide To Field Identification, Macmillan, p. 12, ISBN 1-58238-126-7.
  16. ↑ Young, Charles Augustus (1919), Anne Sewell Young, ed., The Elements of Astronomy: a Textbook, Ginn and company, p. 69, retrieved 2009-10-12.
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