518 research outputs found
Angular momentum transport by internal gravity waves. IV - Wave generation by surface convection zone, from the pre-main sequence to the early-AGB in intermediate mass stars
This is the fourth in a series of papers that deal with angular momentum
transport by internal gravity waves in stellar interiors. Here, we want to
examine the potential role of waves in other evolutionary phases than the main
sequence. We study the evolution of a 3Msun Population I model from the
pre-main sequence to the early-AGB phase and examine whether waves can lead to
angular momentum redistribution and/or element diffusion at the external
convection zone boundary. We find that, although waves produced by the surface
convection zone can be ignored safely for such a star during the main sequence,
it is not the case for later evolutionary stages. In particular, angular
momentum transport by internal waves could be quite important at the end of the
sub-giant branch and during the early-AGB phase. Wave-induced mixing of
chemicals is expected during the early-AGB phase.Comment: A&A in press; 11 figure
Angular Momentum Transport by Internal Gravity Waves. I - Pop I Main Sequence Stars
We examine the generation of gravity waves by the surface convection zone of
low-mass main sequence stars with solar metallicity. It is found that the total
momentum luminosity in waves rises with stellar mass, up to the
quasi-disappearance of the convection zone around 6500K (corresponding to a
mass of about 1.4 Msun for solar metallicity) where the luminosity drastically
drops. We calculate the net momentum extraction associated with these waves and
explain how the calculated mass dependence helps resolve the enigma of the Li
dip in terms of rotational mixing, forming a coherent picture of mixing in all
main sequence stars.Comment: Accepted for publication in A&
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