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.

Xi Draconis (ξ Dra, ξ Draconis) is the Bayer designation for a star in the northern circumpolar constellation of Draco. It has the traditional name Grumium or Genam. This star, along with β Dra (Rastaban), γ Dra (Eltanin), μ Dra (Erakis) and ν Dra (Kuma) were Al ʽAwāïd, "the Mother Camels", which was later known as the Quinque Dromedarii.[7] This star 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 Earth.[1] At this distance, the apparent magnitude is diminished by 0.03 from extinction caused by intervening gas and dust.[4]

In Chinese, 天棓 (Tiān Bàng), meaning Celestial Flail, refers to an asterism consisting of ξ Draconis, ν Draconis, β Draconis, γ Draconis and ι Herculis.[8] Consequently, δ Draconis itself is known as 天棓一 (Tiān Bàng yī, English: the First Star of Celestial Flail.)[9]


Xi Draconis is of spectral class K2-III.


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


  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, arXiv:0708.1752free to read, Bibcode:2007A&A...474..653V, 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, arXiv:astro-ph/0409579free to read, Bibcode:2005A&A...430..165F, 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, arXiv:0801.2155free to read, Bibcode:2008ApJ...674L..53S, 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. ^ 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. 
  8. ^ (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.
  9. ^ (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.