Zeta Horologii

Zeta Horologii
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Horologium
Right ascension 02h 40m 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]
Distance160 ± 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
Mass1.43[6] M☉
Luminosity16.7[5] L☉
Surface gravity (log g)3.74[7] cgs
Temperature6,702[7] K
Metallicity [Fe/H]−0.07[7] dex
Rotational velocity (v sin i)8.0±1.2[3] km/s
Age1.50[7] Gyr
ζ Hor B
Mass1.26[6] M☉
Other designations
ζ Hor, CPD−55° 446, FK5 1076, HD 16920, HIP 12484, HR 802, SAO 232857[8]
Database references
SIMBADdata

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.[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 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.[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]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Corben1968 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Torres2006 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Sahade1964 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Tokovinin2006 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference Casagrande2011 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Trilling2007 was invoked but never defined (see the help page).