Phi Draconis

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Phi Draconis
Draco constellation map.png
Location of φ Draconis (next to χ Dra).
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension 18h 20m 45.4304s[1]
Declination 71° 20′ 16.132″[1]
Apparent magnitude (V) 4.2004[2]
Spectral type B8V[1]
U−B color index -0.38[3]
B−V color index -0.10[3]
Variable type α² CVn[4]
Radial velocity (Rv) -16 [1] km/s
Proper motion (μ) RA: -5.03[2] mas/yr
Dec.: 37.86[2] mas/yr
Parallax (π) 10.77 ± 0.38[2] mas
Distance 300 ± 10 ly
(93 ± 3 pc)
Absolute magnitude (MV) +0.21[5]
Mass 2.99 ± 0.10[5] M
Radius 2.7 ± 0.2[5] R
Luminosity 107[5] L
Surface gravity (log g) 4.21 ± 0.08[5] cgs
Temperature 11,429[5] K
Rotation 1.71649[5]
Other designations
φ Dra, 43 Dra, BD 71° 889, CCDM J18208+7120AB, GC 25114, HD 170000, HIP 89908, HR 6920, SAO 9084
Database references

Phi Draconis (φ Dra / φ Draconis) is a fourth-magnitude star in the constellation Draco. It has the Flamsteed designation 43 Draconis.

In Chinese astronomy, Phi Draconis is called 柱史, Pinyin: Zhùshǐ, meaning Official of Royal Archives, because this star is marking itself and stand alone in Official of Royal Archives asterism, Purple Forbidden enclosure (see : Chinese constellation).[6] Possibly, 柱史 (Zhùshǐ) westernized into Kwei She by R.H. Allen, with the unknown meaning, but it was for χ Dra[7]

See also[edit]


  1. ^ a b c d "* phi Dra". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-11-21. 
  2. ^ a b c d van Leeuwen, F. (November 2007). "Hipparcos, the New Reduction" (VizieR). Astronomy and Astrophysics. Centre de Données astronomiques de Strasbourg. 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752Freely accessible. doi:10.1051/0004-6361:20078357. Retrieved 2010-11-22. 
  3. ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV data. (PDF) origin: SIMBAD. Bibcode:1986EgUBV........0M. 
  4. ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  5. ^ a b c d e f g North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, Bibcode:1998A&A...334..181N, arXiv:astro-ph/9802286Freely accessible 
  6. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日
  7. ^ Star Name - R.H. Allen p.212

External links[edit]

Coordinates: Sky map 18h 20m 45.43s, +71° 20′ 16.13″