Zeta Ophiuchi is a star located in the constellation of Ophiuchus. It has an apparent visual magnitude of 2.57, making it the third-brightest star in the constellation. Parallax measurements give an estimated distance of roughly 366 light-years from the Earth.

Surface temperature: 34,000 K

Mass: 3.978 × 10^31 kg (20 M☉)

Magnitude: 2.569

Spectral type: O9.5 V

B−V color index: +0.032

U−B color index: –0.857