Constraints on parameters of B-type pulsators from combined multicolour photometry and radial velocity data

I. β Cephei stars

¹ Instytut Astronomiczny, Uniwersytet Wrocławski, ul. Kopernika 11, 51-622 Wrocław, Poland e-mail: daszynska@astro.uni.wroc.pl
² Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw, Poland
³ Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warsaw, Poland
⁴ Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya Str. 48, 109017 Moscow, Russia

Received: 13 January 2005
Accepted: 6 June 2005

Abstract

We analyze data on pulsation amplitudes and phases for two β Cephei stars, δ Cet and ν Eri. Strömgren photometry and radial velocity measurements are used simultaneously to obtain constraints on mean parameters of the stars and identification of the excited modes. The inference about the radial mode order and mean star parameters is based on comparison of certain complex parameter, f, determined from data, with its counterpart derived from linear nonadiabatic modelling of stellar oscillations. The theoretical f values are very sensitive to the adopted opacity data. In our modelling we rely on the data from OPAL and OP projects. Significant differences were found. New seismic models of ν Eri were constructed with both the OPAL and OP opacities.