Rho Draconis

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Rho Draconis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Draco
Right ascension 20h 02m 49.07268s[1]
Declination +67° 52′ 24.8294″[1]
Apparent magnitude (V) 4.52[2]
Spectral type K3 III[3]
U−B color index +1.54[2]
B−V color index +1.34[2]
Radial velocity (Rv) −9.80±0.43[4] km/s
Proper motion (μ) RA: +16.44[1] mas/yr
Dec.: +47.31[1] mas/yr
Parallax (π) 7.61 ± 0.17[1] mas
Distance 429 ± 10 ly
(131 ± 3 pc)
Absolute magnitude (MV) −0.97[5]
Radius 28[3] R
Luminosity 402[6] L
Surface gravity (log g) 1.90[7] cgs
Temperature 4370[7] K
Metallicity [Fe/H] 0.03[7] dex
Rotational velocity (v sin i) 10[8] km/s
Other designations
ρ Dra, 67 Dra, BD+67° 1222, HD 190940, HIP 98702, HR 7685, SAO 18676[9]
Database references

Rho Draconis (ρ Dra) is a solitary[10] star in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye with an apparent visual magnitude is 4.52.[2] Based upon an annual parallax shift of 7.61 mas as measured from Earth,[1] it is located around 429 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.027 due to interstellar dust.[5]

With a stellar classification of K3 III,[3] Rho Draconis is a normal giant star that is past the first dredge-up phase of its post-main sequence evolution.[7] It has the peculiar spectrum of a CN star, showing abnormal line strengths for cyanogen and calcium.[11] The star has expanded to around 28[3] times the Sun's radius and it is radiating 402[6] times the solar luminosity from its photosphere at an effective temperature of 4,370 K.[7]


  1. ^ a b c d e f van Leeuwen, F. (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. ^ a b c d Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society, 133: 475–493, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475. 
  3. ^ a b c d Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (3rd ed.), 367: 521–524, arXiv:astro-ph/0012289Freely accessible, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451. 
  4. ^ Famaey, B.; et al. (2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430: 165–186, arXiv:astro-ph/0409579Freely accessible, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272. 
  5. ^ a b Ryon, Jenna; et al. (August 2009), "Comparing the Ca ii H and K Emission Lines in Red Giant Stars", Publications of the Astronomical Society of the Pacific, 121 (882): 842, arXiv:0907.3346Freely accessible, Bibcode:2009PASP..121..842R, doi:10.1086/605456. 
  6. ^ a b McDonald, I.; et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society, 427: 343, arXiv:1208.2037Freely accessible, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x. 
  7. ^ a b c d e Mishenina, T. V.; et al. (October 1995), "Chemical composition of five giants with positive CN-indices.", Astronomy and Astrophysics Supplement, 113: 333, Bibcode:1995A&AS..113..333M. 
  8. ^ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1), Bibcode:1970CoAsi.239....1B. 
  9. ^ "rho Dra -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-05-30. 
  10. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878Freely accessible. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. 
  11. ^ Mishenina, T. V.; Tsymbal, V. V. (September 1997), "Li and CNO abundances in the atmospheres of nine peculiar giants", Astronomy Letters, 23 (5): 609−614, Bibcode:1997AstL...23..609M.