The CoRoT evolution and seismic tools activity

Abstract

The forthcoming data expected from space missions such as CoRoT require the capacity of the available tools to provide accurate models whose numerical precision is well above the expected observational errors. In order to secure that these tools meet the specifications, a team has been established to test and, when necessary, to improve the codes available in the community. The CoRoT Evolution and Seismic Tool Activity (ESTA) has been set up with this mission. Y. Lebreton ( ) · ESTA TeamSeveral groups have been involved. The present paper describes the motivation and the organisation of this activity, providing the context and the basis for the presentation of the results that have been achieved so far. This is not a finished task as future even better data will continue to demand more precise and complete tools for asteroseismology.

CoRoT/ESTA–TASK 1 and TASK 3 comparison of the internal structure and seismic properties of representative stellar models

“…In the following we briefly recall the specifications and tools of TASK 1 and TASK 3 that have been presented in detail by Lebreton et al (2007a).…”

“…As a result, we aim at improving the stellar evolution codes to get a good agreement between models built with different codes and same input physics. For that purpose, several study cases have been defined that cover a large range of stellar masses and evolutionary stages and stellar models have been calculated without (in TASK 1) or with (in TASK 3) microscopic diffusion (see Monteiro et al 2006;Lebreton et al 2007a).…”

Reference grids of stellar models and oscillation frequencies

“…Up to now these reference grids have been used to locate CoRoT potential targets in the H-R diagram in the process of target selection (see Fig. 1 in Lebreton et al, 2007a) and to study some δ Scuti candidates for CoRoT (Poretti et al, 2005).…”

“…These stellar models have been calculated either with the CESAM or the CLES code and the oscillation frequencies have been calculated either with the ADIPLS, POSC or LOSC code. All this material (codes and grids) is described in this volume by Lebreton et al (2007a); Montalbán et al (2007a); Marques et al (2007). We point out that the thorough comparisons of the stellar evolutionary codes and oscillations codes performed under ESTA have shown very good agreement between models calculated by the CESAM and CLES codes which gives us confidence in the use of the present grids (see Lebreton et al, 2007b;Montalbán et al, 2007b;Moya et al, 2007).…”

Thorough analysis of input physics in CESAM and CLÉS codes

“…The models calculated for TASK 1 were based on rather simple input physics. Moreover, a great effort was done to reduce at maximum the differences between computations by fixing the values of fundamental constants and the physics to be used (see Lebreton et al 2008b). In spite of that, some differences among stellar models computed by different codes persist.…”