Alpha2 Capricorni
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Capricornus |
| Right ascension | 20h 18m 03.25595s |
| Declination | −12° 32′ 41.4684″ |
| Apparent magnitude (V) | +3.57 |
| Characteristics | |
| Spectral type | G8.5III-IV |
| U−B color index | +0.69 |
| B−V color index | +0.94 |
| Astrometry | |
| Radial velocity (Rv) | −0.47±0.47 km/s |
| Proper motion (μ) | RA: +62.63 mas/yr Dec.: +2.66 mas/yr |
| Parallax (π) | 31.9795±0.3485 mas |
| Distance | 102 ± 1 ly (31.3 ± 0.3 pc) |
| Absolute magnitude (MV) | +0.98+0.07 −0.06 |
| Details | |
| α2 Cap A | |
| Mass | 2.05±0.29 M☉ |
| Radius | 8.38±0.58 R☉ |
| Luminosity | 40.4±2.2 L☉ |
| Surface gravity (log g) | 3.0 cgs |
| Temperature | 5,030±160 K |
| Metallicity [Fe/H] | −0.15±0.10 dex |
| Rotational velocity (v sin i) | 2.7 km/s |
| Age | 1.30±1.04 Gyr |
| Other designations | |
| Gredi, Algedi, Secunda Giedi, Algiedi Secunda, α2 Cap, 6 Cap, BD−12°5685, FK5 761, HD 192947, HIP 100064, HR 7754, SAO 163427, ADS 13645, WDS J20181-1233A,BC | |
| Database references | |
| SIMBAD | data |
Alpha2 Capricorni is a triple star system in the southern constellation of Capricornus. It has the proper name Algedi, pronounced /ælˈdʒiːdi/; Alpha2 Capricorni is its Bayer designation. This system is visible to the naked eye as a point of light with an apparent visual magnitude of +3.57. It is separated from the fainter α¹ Capricorni by 0.11° of the sky, a gap just resolvable with the naked eye, similar to Mizar and Alcor. Based on parallax measurements, the star is approximately 101 light-years (31 pc) away from the Sun.