Star in the constellation Ophiuchus
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! style="text-align: center; background-color: #FFFFC0;" colspan="2" | Observation dataEpoch J2000      Equinox J2000
! 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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45 Ophiuchi is a single star in the equatorial constellation of Ophiuchus, along the southern border with Scorpius. It has the Bayer designation d Ophiuchi, while "45 Ophiuchi" is the Flamsteed designation. In the past it had the designation Theta Telescopii. This object is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.28. It is located approximately 111.6 light years away from the Sun based on parallax. The star is drifting further from the Earth with a heliocentric radial velocity of +38 km/s.
This object has a stellar classification of F5III-IV, matching an F-type star with a luminosity class displaying mixed traits of a subgiant and a giant star. It is 1.2 billion years old with 1.7 times the mass of the Sun and 3.2 times the Sun's radius. The star is radiating 19 times the luminosity of the Sun from its photosphere at an effective temperature of 6,750 K. It is spinning with a projected rotational velocity of 65 km/s.
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