![]() ![]() The red dot shows the location of α Corona Borealis. |
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Observation data Epoch J2000 Equinox J2000 |
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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.
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Database references | |
SIMBAD | data |