A theoretical approach for the interpretation of pulsating PMS intermediate-mass stars

¹ INAF – Osservatorio Astronomico di Capodimonte, via Moiariello 16, 80131 Napoli, Italy e-mail: [ruoppo;marconi;ripepi]@na.astro.it
² Dipartimento di Scienze Fisiche, Università Federico II, Complesso Monte S. Angelo, 80126 Napoli, Italy
³ Grupo de Astrofísica da Universidade de Coimbra, Departamento de Matemática – FCTUC, Portugal
⁴ Departamento de Matemática Aplicada, Faculdade de Ciências da Universidade do Porto, Portugal
⁵ Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal e-mail: [jmarques;mjm]@astro.up.pt
⁶ DASC and Institut for Fysik og Astronomi, Aarhus Universitet, Denmark e-mail: jcd@phys.au.dk
⁷ INAF – Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy e-mail: palla@arcetri.astro.it

Received: 16 November 2006
Accepted: 29 January 2007

Abstract

Context.The investigation of the pulsation properties of pre-main-sequence intermediate-mass stars is a promising tool to evaluate the intrinsic properties of these stars and to constrain current evolutionary models. Many new candidates of this class have been discovered during the last decade and very accurate data are expected from space observations obtained for example with the CoRoT satellite.

Aims.In this context we aim at developing a theoretical approach for the interpretation of observed frequencies, both from the already available ground-based observations and from the future more accurate and extensive CoRoT results.

Methods.To this purpose we have started a project devoted to the computations of fine and extensive grids of asteroseismic models of intermediate mass pre-main-sequence stars. The obtained frequencies are used to derive an analytical relation between the large frequency separation and the stellar luminosity and effective temperature and to develop a tool to compare theory and observations in the echelle diagram.

Results.The predictive capabilities of the proposed method are verified through the application to two test stars. As a second step, we apply the procedure to two true observations from multisite campaigns and we are able to constrain their stellar parameters, in particular the mass, in spite of the small number of frequencies.

Conclusions.We expect that with a significantly higher number of frequencies both the stellar mass and age could be constrained and, at the same time, the physics of the models could be tested.