63 Ophiuchi [SEP] constellation
63 Ophiuchi
63 Ophiuchi is an O-type giant star in the constellation Sagittarius, despite its name. During a 2009 survey for companions of massive stars, it was observed using speckle interferometry but no companion was found. Uncertain negative parallax measurements of –0.77 ± 0.40 mas suggest that this extremely luminous star may be located about 4000 light-years away. An estimate of the distance based on the strength of the Ca II line yields a more modest value of . The star lies only 0.3° north of the galactic
Delta Ophiuchi
Delta Ophiuchi (δ Ophiuchi, abbreviated Delta Oph, δ Oph), formally named Yed Prior , is a star in the constellation of Ophiuchus. It forms a naked eye optical double with Epsilon Ophiuchi (named "Yed Posterior"). The apparent visual magnitude is 2.75, making this a third-magnitude star and the fourth-brightest in the constellation. Parallax measurements from the Hipparcos spacecraft yield a distance estimate of approximately from the Sun (Epsilon Ophiuchi is approximately ).
Nomenclature.
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