We present a seismic study of the \beta Cephei star \theta Ophiuchi .
Our analysis is based on the observation of one radial mode , one rotationally split \ell = 1 triplet and three components of a rotationally split \ell = 2 quintuplet for which the m -values were well identified by spectroscopy .
We identify the radial mode as fundamental , the triplet as p _ { 1 } and the quintuplet as g _ { 1 } .
Our NLTE abundance analysis results in a metallicity and CNO abundances in full agreement with the most recent updated solar values .
With X \in [ 0.71 , 0.7211 ] and Z \in [ 0.009 , 0.015 ] , and using the Asplund et al .
( ( 4 ) ) mixture but with a Ne abundance about 0.3 dex larger ( Cunha et al . ( 10 ) ) , the matching of the three independent modes , enables us to deduce constrained ranges for the mass ( M = 8.2 \pm 0.3 M _ { \odot } ) and central hydrogen abundance ( X _ { c } = 0.38 \pm 0.02 ) of \theta Oph and to prove the occurrence of core overshooting ( \alpha _ { ov } = 0.44 \pm 0.07 ) .
We also derive an equatorial rotation velocity of 29 \pm 7 km s ^ { -1 } .
Moreover , we show that the observed non-equidistance of the \ell = 1 triplet can be reproduced by second order effects of rotation .
Finally , we show that the observed rotational splitting of two modes can not rule out a rigid rotation model .