Xi Draconis

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Xi Draconis
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension 17h 53m 31.72962s[1]
Declination +56° 52′ 21.5143″[1]
Apparent magnitude (V) 3.75[2]
Spectral type K2 III[3]
U−B color index +1.21[2]
B−V color index +1.18[2]
Radial velocity (Rv) -26.38 ± 0.20[4] km/s
Proper motion (μ) RA: 93.82 ± 0.14[1] mas/yr
Dec.: 78.50 ± 0.12[1] mas/yr
Parallax (π) 28.98 ± 0.12[1] mas
Distance 112.5 ± 0.5 ly
(34.5 ± 0.1 pc)
Mass 1.45 ± 0.17[5] M
Radius 12[6] R
Luminosity 49 ± 4[5] L
Surface gravity (log g) 2.3[6] cgs
Temperature 4,445[5] K
Metallicity [Fe/H] –0.09[6] dex
Rotational velocity (v sin i) 2.3[6] km/s
Other designations
32 Dra, BD+56 2033, FK5 671, HD 163588, HIP 87585, HR 6688, SAO 30631.
Database references

Xi Draconis (ξ Draconis, abbreviated Xi Dra, ξ Dra), also named Grumium,[7] is a star in the northern circumpolar constellation of Draco. It has an apparent visual magnitude of 3.75.[2] Based upon parallax measurements, it is located at a distance of 112.5 light-years (34.5 parsecs) from the Sun.[1] At this distance, the apparent magnitude is diminished by 0.03 from extinction caused by intervening gas and dust.[4]


ξ Draconis (Latinised to Xi Draconis) is the star's Bayer designation.

It bore the traditional name Grumium (or Genam). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[8] to catalogue and standardize proper names for stars. The WGSN approved the name Grumium for this star on 12 September 2016 and it is now so entered in the IAU Catalog of Star Names.[7]

This star, along with Beta Draconis (Rastaban), Gamma Draconis (Eltanin), Mu Draconis (Erakis) and Nu Draconis (Kuma) were Al ʽAwāïd "the Mother Camels", which was later known as the Quinque Dromedarii.[9]

In Chinese, 天棓 (Tiān Bàng), meaning Celestial Flail, refers to an asterism consisting of Xi Draconis, Nu Draconis, Beta Draconis, Gamma Draconis and Iota Herculis.[10] Consequently, Xi Draconis itself is known as 天棓一 (Tiān Bàng yī, English: the First Star of Celestial Flail.)[11]


USS Grumium (AK-112) was a United States Navy Crater class cargo ship named after the star.


Xi Draconis is of spectral class K2-III.


  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society, 172: 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667. 
  3. ^ Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29–50, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333. 
  4. ^ a b Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, Bibcode:2005A&A...430..165F, arXiv:astro-ph/0409579Freely accessible, doi:10.1051/0004-6361:20041272. 
  5. ^ a b c Stello, D.; et al. (2008), "Oscillating K Giants with the WIRE Satellite: Determination of Their Asteroseismic Masses", The Astrophysical Journal Letters, 674 (1): L53–L56, Bibcode:2008ApJ...674L..53S, arXiv:0801.2155Freely accessible, doi:10.1086/528936. 
  6. ^ a b c d Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209. 
  7. ^ a b "IAU Catalog of Star Names". Retrieved 28 July 2016. 
  8. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016. 
  9. ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc., p. 207, ISBN 0-486-21079-0, retrieved 2010-12-12. 
  10. ^ (in 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.
  11. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived January 30, 2011, at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.