A challenge for the stellar model community defined at the Leiden Lorentz Center meeting "Fine-tuning Stellar Population Models" to be presented at IAU symposium 241 "Stellar Populations as Building Blocks of Galaxies"
A second challenge, defined for the Leiden Lorentz Center Workshop "The Giant Branches", to extend the previous one to the red giant phase of low-mass stars.
A model comparison related to the KEPLER mission, as part of Working Group 8 (Red Giants), subgroup 3 (Stellar Modelling) of the Kepler Asteroseismic Science Consortium.
For well-defined specifications of the constitutional physics stellar models are expected to agree to the per cent level or better with respect to global quantities, such as luminosity and radius, and the interior structure. The project is to start with stellar models for early evolutionary phases, to be expanded later to advanced stages. With such calibrated stellar models stellar population synthesis models can more reasonably be compared to observations under variation of chemical composition and population age.
In the first phase (2006) no comparisons with observed objects, such as
eclipsing binaries, open and globular clusters, or individual stars was
part of the project, which was therefore purely theoretical in its
nature. The models provided were presented and discussed during a "challenge"
session at IAU 241.
In the second phase (2009), a comparison with "observed" effective
temperatures of red giants was included.
For the COROT asteroseismology satellite a working group has been constituted under the name ESTA (Evolution and Seismic Tools Activity), which is doing a very similar project. The Stellar Code Calibration project has decided to follow many of their decisions and even to adopt some of their case specifications, which can be found at http://www.astro.up.pt/corot, from where also results and more information is available.
Everyone modelling stars is welcome to adopt our specifications and to participate. Data deposition and access to some data or tools will be available for registered participants only. In case of interest please contact Achim Weiss.
Note: For the KEPLER challenge 2009, participants have to be accepted members of the KASC.Participants should follow the specifications below as closely as possible. They should select cases in the order of the listing below. Models and other output should be uploaded here. For the interior structure, the GONG-format has to be chosen. For HRD-information, ASCII tables with age, log L, log Teff, and similar quantities should be sufficient. The format should follow that given here.
Iterations are possible for early uploads. In that case comparisons and corrections/improvements of models can be done.