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Draco constellation map.svg
Red circle.svg
Location of Alruba (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Draco
Right ascension  17h 43m 59.17049s[1]
Declination +54° 48′ 06.1637″[1]
Apparent magnitude (V) 5.76[2]
Spectral type A0V[3]
Radial velocity (Rv)−2.0[4] km/s
Proper motion (μ) RA: 17.450[1] mas/yr
Dec.: −18.125[1] mas/yr
Parallax (π)7.1436 ± 0.0605[1] mas
Distance457 ± 4 ly
(140 ± 1 pc)
Mass2.4[5] M
Surface gravity (log g)4.0[5] cgs
Temperature10,000[5] K
Age58[5] Myr
Other designations
Alruba, HD 161693, HR 6618, BD+53° 1978, HIP 86782, SAO 30538[6]
Database references

Alruba /ælˈrbə/, designated HD 161693 and HR 6618,[7] is a star in the northern circumpolar constellation of Draco. Based on parallax measurements obtained during the Gaia mission, it is about 457 light-years (140 parsecs) distant from the Sun.


HD 161693 is the star's entry in the Henry Draper Catalogue and HR 6618 that in the Bright Star Catalogue.

It bore the traditional Arabic name الربع Al Rubaʽ "the foal" (specifically a young camel born in the spring), a member of the Mother Camels asterism in early Arabic astronomy.[8][9]

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[10] to catalogue and standardize proper names for stars. The WGSN approved the name Alruba for this star on 1 June 2018 and it is now so entered on the List of IAU-approved Star Names.[7]


This star is a A-type main sequence star with a stellar classification of A0 V.[3]


  1. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  2. ^ Oja, T. (March 1985), "UBV photometry of stars whose positions are accurately known. II", Astronomy and Astrophysics Supplement Series, 59: 461–464, Bibcode:1985A&AS...59..461O
  3. ^ a b Abt, Helmut A; Morrell, Nidia I (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  4. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  5. ^ a b c d Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah (2016). "The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars". The Astronomical Journal. 152 (2): 40. arXiv:1604.06456. Bibcode:2016AJ....152...40G. doi:10.3847/0004-6256/152/2/40.
  6. ^ "HD 161693 -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2018-07-01.
  7. ^ a b "Naming Stars". Retrieved 2018-07-01.
  8. ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (rep. ed.). New York, NY: Dover Publications Inc. pp. 207–212. ISBN 0-486-21079-0.
  9. ^ Garfinkle, Robert A. (2008). Star-Hopping: Your Visa to Viewing the Universe (2nd ed.). Cambridge University Press. p. 183. ISBN 978-0521598897. Retrieved 16 October 2016.
  10. ^ "International Astronomical Union | IAU". Retrieved 2018-07-01.