| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Horologium |
| Right ascension | 02h40m 39.61286s[1] |
| Declination | −54° 32′ 59.6836″[1] |
| Apparent magnitude (V) | 5.20[2] |
| Characteristics | |
| Spectral type | F6 V[3] (F2 V + F5 V)[4] |
| B−V color index | +0.42[2] |
| Astrometry | |
| Radial velocity (Rv) | 5.8[3] km/s |
| Proper motion (μ) | RA: +32.86[1] mas/yr Dec.: +4.96[1] mas/yr |
| Parallax (π) | 20.37 ± 0.21 mas[1] |
| Distance | 160 ± 2 ly (49.1 ± 0.5 pc) |
| Absolute magnitude (MV) | +1.76[5] |
| Orbit[4] | |
| 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[6] M☉ |
| Luminosity | 16.7[5] L☉ |
| Surface gravity (log g) | 3.74[7] cgs |
| Temperature | 6,702[7] K |
| Metallicity [Fe/H] | −0.07[7] dex |
| Rotational velocity (v sin i) | 8.0±1.2[3] km/s |
| Age | 1.50[7] Gyr |
| ζ Hor B | |
| Mass | 1.26[6] M☉ |
| Other designations | |
ζ Hor, CPD−55° 446, FK5 1076, HD 16920, HIP 12484, HR 802, SAO 232857[8] | |
| Database references | |
| SIMBAD | data |
Zeta Horologii, Latinized from ζ Horologii, is a yellow-white-hued binary star system in the southern constellationofHorologium. It is visible to the naked eye with a combined apparent visual magnitude of 5.20.[2] Based upon an annual parallax shift of 20.37 mas as seen from Earth,[1] it is located around 160 light-years from the Sun.
This system was determined to be a double-lined spectroscopic binarybyJ. 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.[4] 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.[9]
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