Alpha Coronae Borealis A/B

The red dot shows the location of α Corona Borealis.
Observation data
Epoch J2000      Equinox J2000
Constellation Corona Borealis
Right ascension 15
Declination +26° 42′ 52.895″
Apparent magnitude (V) 2.21 (2.24 / 7.1)
Characteristics
Spectral type A0V/G5V
U−B color index –0.03/—
B−V color index –0.02/—
Variable type Eclipsing binary
Astrometry
Radial velocity (Rv) +1.7 km/s
Proper motion (μ) RA: +120.38 mas/yr
Parallax (π) 43.65 ± 0.79mas
Distance 75 ± 1 ly
(22.9 ± 0.4 pc)
Absolute magnitude (MV) +0.16/+5.05
Orbit
Period (P) 17.3599 d
Semimajor axis (a) 2.981 × 1012 cm
Eccentricity (e) 0.370
Inclination (i) 88.2 ± 0.1°
Argument of periastron (ω)
(primary)
311°
Details
Mass 2.58/0.92M
Radius 2.89–3.04/0.90R
Luminosity 74/0.81L
Surface gravity (log g) 3.89/4.50
Temperature 9,700/5,800K
Rotational velocity (v sin i) 139 km/s
Age 3.14 × 108 years
Other designations
Gemma, Alphekka, Alphecca, Gnosia, Ashtaroth, The Jewel, Gnosia Stella Coronae, 5 CrB, HR 5793, BD +27°2512, HD 139006, GCTP 3519.00, SAO 83893, FK5 578, HIP 76267.
Database references
SIMBAD data

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Alphekka, which is released under the Creative Commons Attribution-Share-Alike License 3.0