On the effect of overshooting as predicted by the modelling of the pre-main sequence evolution of a 2 solar-mass star

• Tipo: Artigo em Revista Científica Internacional
• Data: 2006

Autores

J.P. Marques (Autor) FCUP; Mário João P. F. G. Monteiro (Autor) FCUP; João Fernandes (Autor) FCUP

Revista

Título: Monthly Notices of the Royal Astronomical Society

Vol. 371

Páginas: 293-302

ISSN: 0035-8711

Editora: Oxford University Press

Indexação

ISI Web of Science

Classificação Científica

FOS: Ciências exactas e naturais > Física

CORDIS: Ciências Físicas > Astronomia ; Ciências Físicas > Astronomia > Astrofísica ; Ciências Físicas

Outras Informações

Resumo (PT): We discuss the effects of convective overshooting in the pre-main-sequence (PMS) evolution of intermediate-mass stars, by analysing in detail the early evolution towards the main sequence of a 2 M⊙ stellar model. These effects can be extremely important in the end of the PMS, when the abundances in CNO elements approach the equilibrium in the centre. We provide a possible physical explanation on why a moderate amount of overshooting produces, as the star approaches the zero-age main-sequence, an extra loop in the evolutionary tracks on the Hertzsprung–Russell diagram. An interesting feature is that there is a very well defined amount of overshooting (for a given stellar mass and chemical composition) beyond which a loop is produced. For smaller amounts of overshooting such a loop does not take place and the evolutionary tracks are similar to those found in the literature. The amount of overshooting needed to produce the loop decreases with stellar mass. We discuss the underlining physical reasons for the behaviour predicted by the evolution models and argue that it provides a crucial observational test for convective overshooting in the core of intermediate-mass stars.

Abstract (EN): We discuss the effects of convective overshooting in the pre-main-sequence (PMS) evolution of intermediate-mass stars, by analysing in detail the early evolution towards the main sequence of a 2 M⊙ stellar model. These effects can be extremely important in the end of the PMS, when the abundances in CNO elements approach the equilibrium in the centre. We provide a possible physical explanation on why a moderate amount of overshooting produces, as the star approaches the zero-age main-sequence, an extra loop in the evolutionary tracks on the Hertzsprung–Russell diagram. An interesting feature is that there is a very well defined amount of overshooting (for a given stellar mass and chemical composition) beyond which a loop is produced. For smaller amounts of overshooting such a loop does not take place and the evolutionary tracks are similar to those found in the literature. The amount of overshooting needed to produce the loop decreases with stellar mass. We discuss the underlining physical reasons for the behaviour predicted by the evolution models and argue that it provides a crucial observational test for convective overshooting in the core of intermediate-mass stars.

Idioma: Inglês

Tipo (Avaliação Docente): Científica