Zeta Andromedae
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 00h 47m 20.326s |
| Declination | +24° 16′ 01.84″ |
| Apparent magnitude (V) | 3.92 to 4.14 |
| Characteristics | |
| Spectral type | K1III + KV |
| U−B color index | +0.90 |
| B−V color index | +1.12 |
| R−I color index | +0.59 |
| Variable type | ELL/RS |
| Astrometry | |
| Radial velocity (Rv) | −24.43±0.1 km/s |
| Proper motion (μ) | RA: −101.068 mas/yr Dec.: −80.276 mas/yr |
| Parallax (π) | 18.0083±0.1604 mas |
| Distance | 181 ± 2 ly (55.5 ± 0.5 pc) |
| Absolute magnitude (MV) | +0.14 |
| Orbit | |
| Period (P) | 17.769426 days |
| Semi-major axis (a) | 2.7 R☉ |
| Eccentricity (e) | 0.0 |
| Inclination (i) | 65±5° |
| Details | |
| Aa | |
| Mass | 2.6±0.4 M☉ |
| Radius | 15.9±0.8 R☉ |
| Luminosity | 95.5 L☉ |
| Surface gravity (log g) | 2.8 cgs |
| Temperature | 4,665±140 K |
| Metallicity [Fe/H] | −0.30 dex |
| Rotation | 17.77 days |
| Rotational velocity (v sin i) | 41.4±0.2 km/s |
| Ab | |
| Mass | 0.75 M☉ |
| Other designations | |
| Shimu, ζ And, Zeta Andromedae, Zet And, 34 Andromedae, 34 And, BD+23 106, FK5 27, GC 940, HD 4502, HIP 3693, HR 215, SAO 74267, PPM 90149, CCDM J00473+2416A, WDS 00473+2416A | |
| Database references | |
| SIMBAD | data |
Zeta Andromedae, also named Shimu, is a binary star system in the northern constellation Andromeda. It is visible to the naked eye with an apparent visual magnitude that varies from 3.92 to 4.14 over the course of its 17.7 day orbit. Based on parallax measurements, it is located at a distance of approximately 181 light-years from the Sun. The system is drifting closer with a heliocentric radial velocity of −24.4 km/s.