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

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.

Multi-site photometry of the pulsating Herbig Ae star V346 Ori

“…B.1 for a large frequency separation Δ f = 35.8 μHz. This quantity is evaluated using the analytical relation between the large frequency separation, the stellar luminosity, and the effective temperature derived by Ruoppo et al (2007). As already found in Fig.…”

“…Starting in 2003, our group has applied the multi-site technique to two targets, V351 Ori (Ripepi et al 2003) and IP Per (Ripepi et al 2006b). The observational results obtained for these stars have been interpreted using non-radial adiabatic pulsation theory (see Ruoppo et al 2007). As a continuation of our ongoing project, here we concentrate on the Herbig Ae star V346 Ori.…”

Keplerobservations of A–F pre-main-sequence stars in Upper Scorpius: discovery of six new δ Scuti and one γ Doradus stars

“…The additional information provided by pulsation can be used to construct detailed models of the varying internal structure of these stars as they contract toward the main sequence, in order to compare the predicted frequencies to the observed ones (Ruoppo et al 2007;Di Criscienzo et al 2008;Casey et al 2013). The physics of PMS stellar evolutionary models can therefore be tested.…”

Porto Oscillation Code (posc)

“…Tools are also available to convert almost any available stellar model output to the required format to be used by Posc. The code has been applied to several cases, namely the Sun (Monteiro 1996;Monteiro et al 1996;Monteiro and Thompson 2005) and other stars (Cunha et al 2003;Fernandes and Monteiro 2003), including pre-main sequence models (Ruoppo et al 2007). It has also been used to produce the frequencies of reference grids of stellar evolution models for asteroseismology (Marques et al 2008).…”