Hamal
| 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 | |
| Evolutionary stage | Red giant branch |
| 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 | 15.19±0.1 R☉ |
| Luminosity | 76.2±0.8 L☉ |
| Surface gravity (log g) | 2.3 cgs |
| Temperature | 4,553±15 K |
| Metallicity [Fe/H] | −0.214 dex |
| Rotational velocity (v sin i) | 3.44 km/s |
| Age | 3.4±1.9 Gyr |
| Other designations | |
| Hemal, Hamal, Ras Hammel, El Nath, Arietis, α Ari, Alpha Arietis, Alpha Ari, 13 Arietis, 13 Ari, BD+22 306, FK5 74, GC 2538, GJ 84.3, GJ 9072, HD 12929, HIP 9884, HR 617, SAO 75151, PPM 91373, LTT 10711, NLTT 7032 | |
| Database references | |
| SIMBAD | data |
Hamal, pronounced /ˈhæməl/, is a star in the northern zodiacal constellation of Aries. It has the Bayer designation Alpha Arietis, which is Latinized from α Arietis and abbreviated Alpha Ari or α Ari. This star is visible to the naked eye with an apparent visual magnitude of 2.0. Hamal is the brightest star in the constellation and, on average, the 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 drifting closer to the Sun with a radial velocity of −14 km/s.
This is an aging giant star that may host an orbiting planet with a mass greater than Jupiter.