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Dubhe
binary star in the constellation of Ursa Major / From Wikipedia, the free encyclopedia
Dubhe or Alpha Ursae Majoris is a red giant star in the constellation of Ursa Major. It is 27 times wider than the Sun.
Quick Facts Observation data Epoch J2000 Equinox J2000, Constellation ...
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] |
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 (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 |
Distance | 123 ± 2 ly (37.7 ± 0.7 pc) |
Absolute magnitude (MV) | −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 |
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