Alpha Herculis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| A | |
| Right ascension | 17h 14m 38.853s |
| Declination | +14° 23′ 25.34″ |
| Apparent magnitude (V) | 3.350 (2.7–4.0) |
| B | |
| Right ascension | 17h 14m 39.181s |
| Declination | +14° 23′ 23.98″ |
| Apparent magnitude (V) | 5.322 |
| Characteristics | |
| A | |
| Evolutionary stage | AGB |
| Spectral type | M5 Ib-II |
| U−B color index | +1.01 |
| B−V color index | +1.45 |
| Variable type | SRc |
| B | |
| Spectral type | G8III + A9IV-V |
| Astrometry | |
| Proper motion (μ) | RA: −7.32 mas/yr Dec.: 36.07 mas/yr |
| Parallax (π) | 9.07±1.32 mas |
| Distance | approx. 360 ly (approx. 110 pc) |
| Absolute magnitude (MV) | −2.3 + 1.8 + 2.8 |
| Details | |
| A | |
| Mass | 2.5+1.6 −1.1 M☉ |
| Radius | 284 ± 60, 264–303 R☉ |
| Luminosity | 7,244–9,333 L☉ |
| Surface gravity (log g) | −0.41±0.19 cgs |
| Temperature | 3,155–3,365 K |
| Ba | |
| Mass | ~2.5 M☉ |
| Luminosity | 126 L☉ |
| Temperature | 4,900 K |
| Bb | |
| Mass | ~2 M☉ |
| Luminosity | 26 L☉ |
| Temperature | 7,350 K |
| Age | 0.41–1.25 Gyr |
| Other designations | |
| Ras Algethi, Rasalgethi, α Her, 64 Her, BD+14°3207, HIP 84345, CCDM J17146+1424, AAVSO 1710+14, WDS J17146+1423 | |
| A: HD 156014, HR 6406, SAO 102680 | |
| B: HD 156015, HR 6407, SAO 102681 | |
| Database references | |
| SIMBAD | α Her |
| A | |
| B | |
Alpha Herculis (α Herculis, abbreviated Alpha Her, α Her), also designated Rasalgethi and 64 Herculis, is a multiple star system in the constellation of Hercules. Appearing as a single point of light to the naked eye, it is resolvable into a number of components through a telescope. It has a combined apparent magnitude of 3.08, although the brightest component is variable in brightness. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 360 light-years (110 parsecs) distant from the Sun. It is also close to another bright star Rasalhague in the vicinity.