Cygnus OB2-8A
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 33m 15.07905s |
| Declination | +41° 18′ 50.4762″ |
| Apparent magnitude (V) | 9.06 |
| Characteristics | |
| Spectral type | O6If + O5.5III(f) |
| U−B color index | +0.15 |
| B−V color index | +1.29 |
| Astrometry | |
| Radial velocity (Rv) | 125.56 km/s |
| Proper motion (μ) | RA: −2.664 mas/yr Dec.: −4.895 mas/yr |
| Parallax (π) | 0.6058±0.0191 mas |
| Distance | 5,400 ± 200 ly (1,650 ± 50 pc) |
| Absolute magnitude (MV) | −6.78 |
| Orbit | |
| Period (P) | 21.9 days |
| Semi-major axis (a) | 71 R☉ |
| Eccentricity (e) | 0.24 |
| Semi-amplitude (K1) (primary) | 82.8 km/s |
| Semi-amplitude (K2) (secondary) | 95.8 km/s |
| Details | |
| Cyg OB2 #8A1 | |
| Mass | 44.1 M☉ |
| Radius | 20 R☉ |
| Luminosity | 650,000 L☉ |
| Surface gravity (log g) | 3.48 cgs |
| Temperature | 36,800 K |
| Cyg OB2 #8A2 | |
| Mass | 37.4 M☉ |
| Radius | 14.8 R☉ |
| Luminosity | 468,000 L☉ |
| Surface gravity (log g) | 3.67 cgs |
| Temperature | 39,200 K |
| Age | 2 Myr |
| Other designations | |
| Schulte 8A, 1E 203127+4108.5, TYC 3161-1325-1, ADS 14000 A, 2E 4382, HIP 101425, UBV 17839, AG+41°1925, 2E 2031.4+4108, IDS 20297+4058, LS III +41 37, Cyg OB2-8A, 1ES 2031+41.1, 2MASS J20331508+4118504, BD+40 4227, GCRV 20036, PPM 60129, CCDM J20332+4119A, 1RXS J203315.8+411848, CGO 605, GOS G080.22+00.79 01, SAO 49781, CSI+40 4227 1, GSC 03161-01325, Gaia DR2 2067784624247057920 | |
| Database references | |
| SIMBAD | data |
Cygnus OB2 #8A is a double-lined spectroscopic binary located near the centre of the Cygnus OB2 association located 5,500 light years away.