Seismic modelling of the Cep star EN (16) Lacertae

¹ Institut d'Astrophysique et de Géophysique de Liège, Université de Liège, allée du Six Août 17, 4000 Liège, Belgium
² Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium
³ Odessa Astronomical Observatory and Isaac Newton Institute of Chile, Odessa Branch, Ukraine
⁴ Thüringer Landessternwarte, 07778 Tautenburg, Germany

Corresponding author: A. Thoul, anne.thoul@ulg.ac.be

Received: 12 February 2003
Accepted: 15 May 2003

Abstract

We perform seismic modelling of the massive Cep star EN Lacertae. The starting point of our analysis is the spectroscopic mode identification recently performed. To this, we add a new updated photometric mode identification based upon a non-adiabatic description of the eigenfunctions in the outer atmosphere. Both mode identifications agree and this allows us to fine-tune the stellar parameters of EN Lacertae with unprecedented precision. This is done by producing a huge amount of stellar models with different parameters and selecting those that fulfill the frequency values and the mode identification. Our study is the first one of its kind in which a reconcilation between observed pulsational characteristics and theoretical models can be achieved at a level that allows accurate determination of the basic stellar parameters of a massive oscillator. We derive a mass of and an age of 15.7 million years if we assume that convective overshooting does not occur.