Hamal
Hamal /ˈhæməl/, designated Alpha Arietis (α Arietis, abbreviated Alpha Ari, α Ari), is the brightest star in the northern zodiacal constellation of Aries.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Aries |
| Right ascension | 02h 07m 10.40570s |
| Declination | +23° 27′ 44.7032″ |
| Apparent magnitude (V) | 2.00 |
| Characteristics | |
| Spectral type | K1IIIb |
| U−B color index | +1.13 |
| B−V color index | +1.15 |
| V−R color index | +0.7 |
| R−I color index | +0.62 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | −14.2 ± 0.9 km/s |
| Proper motion (μ) | RA: +188.55 mas/yr Dec.: −148.08 mas/yr |
| Parallax (π) | 49.56 ± 0.25 mas |
| Distance | 65.8 ± 0.3 ly (20.2 ± 0.1 pc) |
| Absolute magnitude (MV) | +0.47 ± 0.04 |
| Details | |
| Mass | 1.5 ± 0.2 M☉ |
| Radius | 14.9 ± 0.3 R☉ |
| Luminosity (bolometric) | 91 ± 6 L☉ |
| Surface gravity (log g) | 2.57 cgs |
| Temperature | 4,480 K |
| Metallicity [Fe/H] | −0.25 dex |
| Rotational velocity (v sin i) | 3.44 km/s |
| Age | 3.4 ± 1.9 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
With an apparent visual magnitude of 2.0, it is the mean 50th-brightest star in the night sky. Based upon parallax measurements made with the Hipparcos astrometry satellite, Hamal is about 65.8 light-years (20.2 parsecs) from Earth. It is a giant star that may host an orbiting planet with a mass greater than Jupiter.
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