A& A Supplement series, Vol. 123, June I 1997, 241-272
Received April 22; accepted July 30, 1996
M. Forestini -
C. Charbonnel
Send offprint request: M. Forestini
Laboratoire d'Astrophysique, Observatoire de Grenoble,
Université Joseph Fourier, BP 53, F-38041 Grenoble Cedex 9,
France
Laboratoire d'Astrophysique de Toulouse, CNRS UMR 5572,
Toulouse, France
The structural and nucleosynthetic evolution of 3, 4, 5, 6 and
stars with two metallicities (Z = 0.005 and 0.02) has been computed in
detail, from the early pre-main sequence phase up to the thermally pulsing
(TP) AGB phase or the onset of off-center carbon burning. Typically 10 to
20 thermal pulses have been followed for each TP-AGB object. This
homogeneous and quite large set of models allows us to present an overview
of the thermal pulse properties as well as of the nucleosynthesis
accompanying the TP-AGB phase of intermediate-mass stars.
More specifically, after a brief description of the previous evolutionary
stages, predictions are given for the isotopic ratios involving C, N, O,
Ne, Mg, Al and Si. Also the surface abundances of ,
and
are reported. As the asymptotic phase of
the thermal pulses has been reached for each star, we also indicate how
these abundances will probably evolve until the stars completely loose
their envelope, by including the evolution of the nucleosynthesis itself.
keywords: stars: AGB -- stars: interiors -- stars: nucleosynthesis - stars: abundances