During the past several years, asteroseismologists of the Instituut voor Sterrenkunde of the K.U.Leuven, of the Institut d'Astrophysique et Géophysique of the ULg and of the Royal Observatory have very succesfully collaborated on many different topics in asteroseismology (we refer to the publication list in the annual reports of the previous IUAP). The collaboration is now extended to the Observational Astronomy Group of the V.U.B. This implies the participation of all the members of the Belgian Asteroseismology Group (BAG). The BAG was founded in 2000 with the specific aim to coordinate all the Belgian initiatives and expertises in asteroseismology, in order to orient the relevant research towards the upcoming data of pulsating stars from space. It mostly concerns COROT, a French-led European mission, which is in full preparation at present, with launch foreseen in 2005 and lifetime of about two years. Several members of the BAG are involved in the development of these missions.

1) Hare and Hound exercises for the COROT mission

2) A Cephei stars

3) B and SPB stars

4) Scuti and Doradus stars

5) Solar type stars

6) Variable stars in clusters

Variable stars in star clusters share common ages, original chemical composition and distance, which strongly simplifies the comparison with theoretical models. We take advantage of this when studying pulsating variables in the globular cluster Centauri (though metal abundance is a free parameter in this case), a collaboration between two of the IAP partners and colleagues in Rome (OAR), Germany (AIP) and Denmark (CUAO), and in a second project where we search for open clusters well suited for multi-site campaigns of Sct stars. 7) A and F stars

8) Non-adiabatic analysis

       The study of the non-adiabatic character of stellar oscillations can give precise informations about their internal structure. First, we studied in details the influence non-adiabatic temperature variations on line profile variations of B-type pulsators. Our non-adiabatic pulsation code also allows us to determine the theoretical amplitude ratios and phase differences of the light curve as seen in different colour filters. By confronting these theoretical predictions to the observations, it is possible on one hand to determine the degree l of the modes and, on the other hand, to obtain precise informations about the stars. We call this method Non-adiabatic Asteroseismology. We applied this method to the study of B-type pulsators and showed that strong constraints on the metallicity of these stars can be obtained by this approach. We applied also this method to the study of A- and F-type pulsators, in a close collaboration with the Instituto de Astrofisica de Andalucia, Spain. We showed that the characteristics of the thin convective envelope of these stars can be constrained with this approach. Our last works in this frame have been to include the new ATLAS9 atmosphere models in our non-adiabatic code. These models have been computed using three different convection treatments (mixing length theory -MLT-, Canuto and Mazzitelli (1991), and Canuto, Goldmann and Mazziteli 1996) and therefore allow us to compute complete (atmosphere and interior) stellar models with a consistent treatment of convection.

9) Spectroscopic analysis


       The European Network of Excellence in AsteroSeismology (ENEAS) was created on 11 October 2002 during a kick-off meeting held in Leuven (Belgium) at the initiative of the Belgian Asteroseismology Group. The purpose of ENEAS is to provide an efficient coordination between the numerous, already existing European initiatives in asteroseismology and to achieve an effective integration of all European expertise in this research domain through numerous exchanges of the ENEAS scientists. Another prime goal of ENEAS is to prepare European scientists for the huge databases of seismic data of stars that will be delivered by European space missions, such as COROT and Eddington, in the near future. Any information on ENEAS can be found at the ENEAS web page:

       This web page will gradually include more and more applications, such as basic information about ENEAS, databases of seismic observations, a database of analysis tools with user-guidelines, outreach material, asteroseismology courses etc. Besides this electronic communication channel, we will publish any ENEAS matters in the journal Communications in Asteroseismology under editorship of M. Breger (Vienna University).

       Meanwhile, 256 scientists from 43 institutes have joined ENEAS.

Web pages:Sandrine Sohy
Last modification: February 16, 2005