Binary star system in the constellation Horologium
! style="text-align: center; background-color: #FFFFC0;" colspan="2" | Observation dataEpoch J2000.0
       Equinox J2000.0 (ICRS)
! style="text-align:left" | Constellation
! style="text-align:left" | Right ascension
! style="text-align:left" | Declination
! style="text-align:left" | Apparent magnitude (V)
! style="background-color: #FFFFC0; text-align: center;" colspan="2"| Characteristics
! style="text-align:left" | Spectral type
! style="text-align:left" | U−B 
! style="text-align:left" | B−V 
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Delta Horologii (δ Horologii) is a binary star system in the constellation Horologium. It is visible to the naked eye with a combined apparent visual magnitude of 4.93. As of 2014, the pair had an angular separation of 0.20 arc seconds along a position angle of 24°. Based upon an annual parallax shift of 18.24 mas as seen from Earth, it is located 179 ± 4 light years from the Sun.
The primary, component A, is a magnitude 5.15 A-type main sequence star with a stellar classification of A9 V. At the estimated age of 768 million years, it is spinning rapidly with a projected rotational velocity of 220 km/s, giving the star an oblate shape with an equatorial bulge that is 15% larger than the polar radius. The star has 1.4 times the mass of the Sun.
The secondary has an apparent magnitude of 7.29.
References.
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