binary star in the constellation of Ursa Major

Dubhe or Alpha Ursae Majoris is a red giant star in the constellation of Ursa Major. It is 27 times wider than the Sun.

α Ursae Majoris
Location of α Ursae Majoris (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension  11h 03m 43.67152s[1]
Declination +61° 45′ 03.7249″[1]
Apparent magnitude (V) 1.79[2]
Spectral type K0III[3] + F0V[4]
U−B color index +0.93[2]
B−V color index +1.07[2]
Variable type Suspected[5]
Radial velocity (Rv)−9.4±0.3[6] km/s
Proper motion (μ) RA: –134.11[1] mas/yr
Dec.: –34.70[1] mas/yr
Parallax (π)26.54 ± 0.48[1] mas
Distance123 ± 2 ly
(37.7 ± 0.7 pc)
Absolute magnitude (MV)−1.10±0.04[7]
α UMa A
Mass3.44±0.11 M
Radius17.03±0.13 R
Luminosity165.1±8.3 L
Surface gravity (log g)2.20 cgs
Temperature5,012±65 K
Metallicity [Fe/H]−0.20±0.07[9] dex
Rotational velocity (v sin i)2.6±1.0[7] km/s
Age280±30 Myr
α UMa B
Mass~1.6[3] M
Other designations
Database references

References change

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. 2.0 2.1 2.2 Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J
  3. 3.0 3.1 Guenther, D. B.; et al. (2000). "Evolutionary Model and Oscillation Frequencies for α Ursae Majoris: A Comparison with Observations". The Astrophysical Journal. 530 (1): L45–L48. Bibcode:2000ApJ...530L..45G. doi:10.1086/312473. PMID 10642202.
  4. Tokovinin, A. A. (1997). "MSC - a catalogue of physical multiple stars". Astronomy and Astrophysics Supplement Series. 124: 75–84. Bibcode:1997A&AS..124...75T. doi:10.1051/aas:1997181.
  5. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  6. Gontcharov, G. A. (November 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. S2CID 119231169.
  7. 7.0 7.1 Carney, Bruce W.; et al. (March 2008), "Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars", The Astronomical Journal, 135 (3): 892–906, arXiv:0711.4984, Bibcode:2008AJ....135..892C, doi:10.1088/0004-6256/135/3/892, S2CID 2756572
  8. Baines, E.; et al. (2017). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1): 30. arXiv:1712.08109. Bibcode:2018AJ....155...30B. doi:10.3847/1538-3881/aa9d8b. S2CID 119427037.
  9. McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527
  10. "DUBHE -- Spectroscopic binary", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-23