Dubhe

α Ursae Majoris
	Location of α Ursae Majoris (circled)
Observation data; Epoch J2000 Equinox J2000
Constellation	Ursa Major
Right ascension	11h 03m 43.67152s
Declination	+61° 45′ 03.7249″
Apparent magnitude (V)	1.79
Characteristics
Spectral type	K0III + F0V
U−B color index	+0.93
B−V color index	+1.07
Variable type	Suspected
Astrometry
Radial velocity (Rv)	−9.4±0.3 km/s
Proper motion (μ)	RA: –134.11 mas/yr ; Dec.: –34.70 mas/yr
Parallax (π)	26.54 ± 0.48 mas
Distance	123 ± 2 ly ; (37.7 ± 0.7 pc)
Absolute magnitude (MV)	−1.10±0.04
Details
α UMa A
Mass	3.44±0.11 M☉
Radius	17.03±0.13 R☉
Luminosity	165.1±8.3 L☉
Surface gravity (log g)	2.20 cgs
Temperature	5,012±65 K
Metallicity [Fe/H]	−0.20±0.07 dex
Rotational velocity (v sin i)	2.6±1.0 km/s
Age	280±30 Myr
α UMa B
Mass	~1.6 M☉
Other designations
	Dubhe, Ak, α Ursae Majoris, α UMa, Alpha UMa, 50 UMa, NSV 5070, BD+62°1161, FK5 417, GC 15185, HD 95689, HIP 54061, HR 4301, SAO 15384, PPM 17705, ADS 8035, CCDM J11037+6145AB, WDS J11037+6145AB
Database references
SIMBAD	data

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

References

↑ ^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.
↑ ^2.0 ^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
↑ ^3.0 ^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.
↑ 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.
↑ 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.
↑ 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.
↑ ^7.0 ^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
↑ 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.
↑ 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
↑ "DUBHE -- Spectroscopic binary", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-23

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[aaa474_2_653-1] 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.

[clpl4_99-2] 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

[guenther-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.

[msc-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.

[gcvs-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.

[Gontcharov2006-6] 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.

[aj135_3_892-7] 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

[Baines_et_al_2017-8] 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.

[ajss74_1075-9] 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

[SIMBAD-10] "DUBHE -- Spectroscopic binary", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-23

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Observation data Epoch J2000 Equinox J2000
Location of α Ursae Majoris (circled)
Constellation	Ursa Major
Right ascension	11^h 03^m 43.67152^s^[1]
Declination	+61° 45′ 03.7249″^[1]
Apparent magnitude (V)	1.79^[2]
Characteristics
Spectral type	K0III^[3] + F0V^[4]
U−B color index	+0.93^[2]
B−V color index	+1.07^[2]
Variable type	Suspected^[5]
Astrometry

Radial velocity (R_v)	−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
Distance	123 ± 2 ly (37.7 ± 0.7 pc)
Absolute magnitude (M_V)	−1.10±0.04^[7]

Details^[8]
α UMa A
Mass	3.44±0.11 `M`_☉
Radius	17.03±0.13 `R`_☉
Luminosity	165.1±8.3 `L`_☉
Surface gravity (log g)	2.20 cgs
Temperature	5,012±65 K
Metallicity [Fe/H]	−0.20±0.07^[9] dex
Rotational velocity (v sin i)	2.6±1.0^[7] km/s
Age	280±30 Myr
α UMa B
Mass	~1.6^[3] `M`_☉
Other designations
Dubhe, Ak, α Ursae Majoris, α UMa, Alpha UMa, 50 UMa, NSV 5070, BD+62°1161, FK5 417, GC 15185, HD 95689, HIP 54061, HR 4301, SAO 15384, PPM 17705, ADS 8035, CCDM J11037+6145AB, WDS J11037+6145AB^[10]
Database references
SIMBAD	data