Multiple 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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Tau Ophiuchi (τ Oph) is a multiple star in the constellation Ophiuchus, approximately 167 light years away based on parallax. Its two main components are two yellow-white main sequence stars, A, of magnitude 5.24 and class F2V, and B, of magnitude 5.94 and class F5V, orbiting each other with a period of 257 years and eccentricity around 0.77. A is reported as a spectroscopic binary with a smaller star of 0.29 solar masses orbiting it every 186 days. An additional component, C, has a separation of 100.8" and magnitude 11.28.
References.
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