An asteroseismic study of the β Cephei star θ Ophiuchi: constraints on global stellar parameters and core overshooting.

We present a seismic study of the β Cephei star θ Ophiuchi. Our analysis is based on the observation of one radial mode, one rotationally split triplet and three components of a rotationally split quintuplet for which the m values were well identified by spectroscopy. We identify the radial mode as fundamental, the triplet as p₁ and the quintuplet as g₁. Our non-local thermodynamic equilibrium abundance analysis results in a metallicity and CNO abundances in full agreement with the most recent updated solar values. With and , and using the Asplund et al. mixture but with a Ne abundance about 0.3 dex larger, the matching of the three independent modes enables us to deduce constrained ranges for the mass and central hydrogen abundance of θ Oph and to prove the occurrence of core overshooting . We also derive an equatorial rotation velocity of . Moreover, we show that the observed non-equidistance of the triplet can be reproduced by the second-order effects of rotation. Finally, we show that the observed rotational splitting of two modes cannot rule out a rigid rotation model. [ABSTRACT FROM AUTHOR]