Zeta Horologii
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Horologium |
| Right ascension | 02h 40m 39.61286s |
| Declination | −54° 32′ 59.6836″ |
| Apparent magnitude (V) | 5.20 |
| Characteristics | |
| Spectral type | F6 V (F2 V + F5 V) |
| B−V color index | +0.42 |
| Astrometry | |
| Radial velocity (Rv) | 5.8 km/s |
| Proper motion (μ) | RA: +32.86 mas/yr Dec.: +4.96 mas/yr |
| Parallax (π) | 20.37±0.21 mas |
| Distance | 160 ± 2 ly (49.1 ± 0.5 pc) |
| Absolute magnitude (MV) | +1.76 |
| Orbit | |
| Period (P) | 12.9274 d |
| Eccentricity (e) | 0.25 |
| Periastron epoch (T) | 7.361±0.046 |
| Argument of periastron (ω) (secondary) | 78.6±0.13° |
| Semi-amplitude (K1) (primary) | 58.1±1.37 km/s |
| Semi-amplitude (K2) (secondary) | 66.1±1.56 km/s |
| Details | |
| ζ Hor A | |
| Mass | 1.43 M☉ |
| Luminosity | 16.7 L☉ |
| Surface gravity (log g) | 3.74 cgs |
| Temperature | 6,702 K |
| Metallicity [Fe/H] | −0.07 dex |
| Rotational velocity (v sin i) | 8.0±1.2 km/s |
| Age | 1.50 Gyr |
| ζ Hor B | |
| Mass | 1.26 M☉ |
| Other designations | |
| ζ Hor, CPD−55°446, FK5 1076, HD 16920, HIP 12484, HR 802, SAO 232857 | |
| Database references | |
| SIMBAD | data |
Zeta Horologii, Latinized from ζ Horologii, is a yellow-white-hued binary star system in the southern constellation of Horologium. It is visible to the naked eye with a combined apparent visual magnitude of 5.20. Based upon an annual parallax shift of 20.37 mas as seen from Earth, it is located around 160 light-years from the Sun.
This system was determined to be a double-lined spectroscopic binary by J. H. Moore in 1911−12. The first orbital elements were published by J. Sahade and C. A. Hernández in 1964, who found it consisted of two F-type main-sequence stars of probable stellar classifications F2 V and F5 V. The pair orbit each other with a period of 12.9274 days and an eccentricity of 0.25. The system displays an infrared excess at a wavelength of 24 μm but not at 70 μm, yielding a derived temperature of 260 K. This suggests a circumbinary debris disk orbiting at a distance of less than 4.8 AU from the star system.