Modelling the oscillating star V1162 Ori

Department of Physics, Middle East Technical University, Inönü Bulvarı, 06531 Ankara, Turkey

Corresponding author: R. Civelek, rikkat@photon.physics.metu.edu.tr

Received: 12 May 2003
Accepted: 12 August 2003

Abstract

Evolutionary stellar models of V1162 Ori, with the latest observations of a multiperiodic δ Scuti star, have been calculated theoretically and compared with the observations. Theoretical models representative of the star indicate that it is at an advanced stage of its main-sequence evolution. Calculations have been made for two different masses, 1.80 and 1.82 , at different rotational speeds. Rotation was treated as a perturbation and only the first-order effect was considered. The evolutionary models were used to obtain the radial and non-radial adiabatic oscillation frequencies and the oscillation equations were treated linearly. The radial fundamental frequency (12.7082 d^-1) named so by the observers and the other observed frequencies were theoretically found from the model (model 4) that is claimed to represent the observed star the best. The agreement with the observations is within a few hundredths of a cycle or better. Since an observational rotational value of  km s^-1 is published in the literature, rotational effects on the oscillation modes were also considered. It is shown that the oscillation frequencies increase with rotational speed for rotational velocities larger than about 50 km s^-1.