10 Draconis

10 Draconis
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension  13h 51m 25.90451s[1]
Declination +64° 43′ 23.7510″[1]
Apparent magnitude (V) 4.66±0.02[2]
Spectral type M3.5 III[3]
B−V color index 1.572±0.010[4]
Radial velocity (Rv)−12.26±0.17[4] km/s
Proper motion (μ) RA: +14.144[1] mas/yr
Dec.: +3.172[1] mas/yr
Parallax (π)8.2082 ± 0.2628[1] mas
Distance400 ± 10 ly
(122 ± 4 pc)
Absolute magnitude (MV)−0.70[4]
Mass0.93±0.06 M
Luminosity1,031±70 L
Surface gravity (log g)1.00 cgs
Temperature3,584±35 K
Metallicity [Fe/H]−0.24 dex
Age10.24±1.40 Gyr
Other designations
i Dra, 10 Dra, CU Dra, BD+65° 963, FK5 511, HD 121130, HIP 67627, HR 5226, SAO 16199[5]
Database references

10 Draconis is a single[6] star in the northern circumpolar constellation of Draco. It was a latter designation of 87 Ursae Majoris,[7] and is visible to the naked eye with an apparent visual magnitude of 4.66.[2] The distance to this star, as determined from its annual parallax shift of 8.2 mas,[1] is around 400 light years. It is moving closer with a heliocentric radial velocity of −12 km/s, and is expected to come to within 84 ly in about 8.6 million years.[4]

Estimated to be around 10 billion years old, this is an aging red giant star with a stellar classification of M3.5 III.[3] It is a periodic variable with a frequency of 11.98912 cycles per day and an amplitude of 0.0254 in magnitude.[8] The spectrum does not show evidence of s-process enhancement.[9] 10 Dra has 93% of the mass of the Sun but has expanded to about 83 times the Sun's radius. The star is radiating over 1,000 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,584 K.[2]


  1. ^ a b c d e f 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. ^ a b c d Baines, E.; Schmitt, H. R.; Zavala, R. T.; Hutter, D.; van Belle, G. T. (December 2017). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1). arXiv:1712.08109. Bibcode:2018AJ....155...30B. doi:10.3847/1538-3881/aa9d8b.
  3. ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
  4. ^ a b c d Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
  5. ^ "HD 40409". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-16.
  6. ^ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
  7. ^ Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy. 18: 223. Bibcode:1987JHA....18..209W. doi:10.1177/002182868701800305.
  8. ^ Koen, Chris; Eyer, Laurent (March 2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society. 331 (1): 45–59. arXiv:astro-ph/0112194. Bibcode:2002MNRAS.331...45K. doi:10.1046/j.1365-8711.2002.05150.x.
  9. ^ Brown, Jeffery A.; et al. (June 1990), "S stars without technetium - The binary star connection", Astronomical Journal, 99: 1930–1940, Bibcode:1990AJ.....99.1930B, doi:10.1086/115475