AB Andromedae
AB Andromedae (AB And) is a binary star in the constellation Andromeda. Paul Guthnick and Richard Prager discovered that the star is an eclipsing binary in 1927. Its maximum apparent visual magnitude is 9.49 but shows a variation in brightness down to a magnitude of 10.46 in a periodic cycle of roughly 8 hours. The observed variability is typical of W Ursae Majoris variable stars, so the two stars in this system form a contact binary.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 23h 11m 32.08609s |
| Declination | +36° 53′ 35.10721″ |
| Apparent magnitude (V) | 9.49 ( – 10.32) – 10.46 |
| Characteristics | |
| Spectral type | G5+G5V |
| Apparent magnitude (B) | 10.62 |
| Apparent magnitude (V) | 9.675 |
| Apparent magnitude (G) | 9.6953 |
| Apparent magnitude (J) | 8.172 |
| Apparent magnitude (H) | 7.805 |
| Apparent magnitude (K) | 7.665 |
| B−V color index | 0.9163 |
| Variable type | EW |
| Astrometry | |
| Radial velocity (Rv) | −27.53±0.67 km/s |
| Proper motion (μ) | RA: 107.923±0.046 mas/yr Dec.: −53.357±0.036 mas/yr |
| Parallax (π) | 11.7027 ± 0.0367 mas |
| Distance | 278.7 ± 0.9 ly (85.5 ± 0.3 pc) |
| Orbit | |
| Period (P) | 0.3319 days |
| Semi-major axis (a) | 2.308 R☉ |
| Eccentricity (e) | 0.002±0.001 |
| Argument of periastron (ω) (secondary) | 40±5° |
| Argument of periastron (ω) (primary) | 220±5° |
| Semi-amplitude (K1) (primary) | 233±1 km/s |
| Semi-amplitude (K2) (secondary) | 133±1 km/s |
| Details | |
| Primary | |
| Mass | 1.04 M☉ |
| Radius | 1.03 R☉ |
| Surface gravity (log g) | 4.392 cgs |
| Temperature | 5,798 K |
| Age | 5.53±2.00 Gyr |
| Secondary | |
| Mass | 0.60 M☉ |
| Radius | 0.78 R☉ |
| Surface gravity (log g) | 4.347 cgs |
| Temperature | 5,450 K |
| Age | 5.53±2.00 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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