Z Andromedae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 23h 33m 39.9551s |
| Declination | +48° 49′ 05.974″ |
| Apparent magnitude (V) | 7.7 - 11.3 |
| Characteristics | |
| Spectral type | M2III + B1eq |
| U−B color index | −0.49 |
| B−V color index | +1.35 |
| Variable type | Z And |
| Astrometry | |
| Radial velocity (Rv) | -0.59 km/s |
| Proper motion (μ) | RA: -1.606 ± 0.049 mas/yr Dec.: -2.971 ± 0.040 mas/yr |
| Parallax (π) | 0.5123±0.0300 mas |
| Distance | 6,400 ± 400 ly (2,000 ± 100 pc) |
| Orbit | |
| Period (P) | 759.0±1.9 days |
| Eccentricity (e) | 0.0 |
| Inclination (i) | 47±12° |
| Semi-amplitude (K1) (primary) | 6.73±0.22 km/s |
| Details | |
| Red giant | |
| Mass | 2 M☉ |
| Radius | 85 R☉ |
| Luminosity | 880 L☉ |
| Temperature | 3,400 K |
| White dwarf | |
| Mass | 0.75 M☉ |
| Radius | 0.17 - 0.36 R☉ |
| Luminosity | 1,500 - 9,800 L☉ |
| Temperature | 90,000 - 150,000 K |
| Rotation | 1682.6 ± 0.6 s |
| Other designations | |
| MWC 416, HD 221650, HIP 116287, SAO 53146, PPM 64386, AG+48° 2087, GCRV 14773, IRAS 23312+4832, HV 193, AN 41.1901, JP11 3636, TYC 3645-2066-1, BD+48° 4093, GSC 03645-02066, 2MASS J23333994+4849059, AAVSO 2328+48, 2E 2331.6+4834, PLX 5697, 2E 4735 | |
| Database references | |
| SIMBAD | data |
| Data sources: | |
| Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) | |
Z Andromedae is a binary star system consisting of a red giant and a white dwarf. It is the prototype of a type of cataclysmic variable star known as symbiotic variable stars or simply Z Andromedae variables. The brightness of those stars vary over time, showing a quiescent, more stable phase and then an active one with a more pronounced variability and stronger brightening and/or dimming.