Alphard
Alphard /ˈælfɑːrd/, designated Alpha Hydrae (α Hydrae, abbreviated Alpha Hya, α Hya), is the brightest star in the constellation of Hydra. It is a single giant star, cooler than the Sun but larger and more luminous. It is about 177 light-years away.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 27m 35.2433s |
| Declination | −08° 39′ 30.969″ |
| Apparent magnitude (V) | +2.00 |
| Characteristics | |
| Spectral type | K3 II-III |
| U−B color index | +1.73 |
| B−V color index | +1.44 |
| Astrometry | |
| Radial velocity (Rv) | −4.3 km/s |
| Proper motion (μ) | RA: −14.49 mas/yr Dec.: 33.25 mas/yr |
| Parallax (π) | 18.40 ± 0.78 mas |
| Distance | 177 ± 8 ly (54 ± 2 pc) |
| Absolute magnitude (MV) | −1.69 ± 0.09 |
| Details | |
| Mass | 3.03 ± 0.36 M☉ |
| Radius | 50.5 ± 4.0 R☉ |
| Luminosity | 780 ± 78 L☉ |
| Surface gravity (log g) | 1.54 cgs |
| Temperature | 4,120 K |
| Metallicity [Fe/H] | −0.06 dex |
| Rotation | 2,991 days |
| Rotational velocity (v sin i) | 1.1 km/s |
| Age | (4.2 ± 1.6) × 108 years |
| Other designations | |
| Database references | |
| SIMBAD | data |
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.