Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-05-05
Astron.Astrophys. 422 (2004) 239-245
Astronomy and Astrophysics
Astrophysics
8 pages, 7 figures, accepted for publication in Astronomy & Astrophysics
Scientific paper
10.1051/0004-6361:20035693
We have produced detailed evolutionary models of the binary EK Cep using the CESAM stellar evolution code (Morel 1997). A $\chi^2$-minimisation was performed to derive the most reliable set of modelling parameters. We have found that an evolutionary age of about 26.8 Myrs fits both components in the same isochrone. The positions of EK Cep A and B in the HR diagram are consistent (within the observational uncertainties) with our results. Our revised calibration shows clearly that EK Cep is in the beginning of the main sequence, while EK Cep B is indeed a PMS star. Such a combination allows for a precise age determination of the binary, and provides a strict test of the modelling. In particular we have found that the definition of the time step in calculating the PMS evolution is crucial to reproduce the observations. A discussion of the optimal time step for calculating PMS evolution is presented. The fitting to the radii of both components is a more difficult task; although we managed to do it for EK Cep B, EK Cep A has a lower radius than our best models. We further studied the effect of the inclusion of a moderate convective overshooting; the calibration of the binary is not significantly altered, but the effect of the inclusion of overshooting can be dramatic in the approach to the main sequence of stars with masses high enough to burn hydrogen through the CNO cycle on the main sequence.
Fernandes Joao
Marques José P.
Monteiro Mario J. F. P. G.
No associations
LandOfFree
The role of the time step and overshooting in the modelling of PMS evolution: the case of EK Cephei does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The role of the time step and overshooting in the modelling of PMS evolution: the case of EK Cephei, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The role of the time step and overshooting in the modelling of PMS evolution: the case of EK Cephei will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-466846