Fingering Convection in Red Giants Revisited
| Autor: | Leandro Gabriel Althaus, F. C. Wachlin, Sylvie Vauclair |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Ciencias Astronómicas
Ciencias Físicas evolution [Stars] FOS: Physical sciences Astrophysics Evolution of stars purl.org/becyt/ford/1 [https] Physics::Fluid Dynamics Astrophysics::Solar and Stellar Astrophysics Abundances Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics Physics Stars: abundances interiors [Stars] Astronomy and Astrophysics purl.org/becyt/ford/1.3 [https] Astronomía Stars: evolution Interior stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Instabilities abundances [Stars] Stars: interiors Humanities CIENCIAS NATURALES Y EXACTAS |
| Zdroj: | SEDICI (UNLP) Universidad Nacional de La Plata instacron:UNLP CONICET Digital (CONICET) Consejo Nacional de Investigaciones Científicas y Técnicas instacron:CONICET |
| Popis: | Context. Fingering (thermohaline) convection has been invoked for several years as a possible extra-mixing which could occur in red giant stars; it is due to the modification of the chemical composition induced by nuclear reactions in the hydrogen burning zone. Recent studies show, however, that this mixing is not sufficient to account for the needed surface abundances. Aims. A new prescription for fingering convection, based on 3D numerical simulations has recently been proposed. The resulting mixing coefficient is larger than those previously given in the literature. We compute models using this new coefficient and compare them to previous studies. Methods. We used the LPCODE stellar evolution code with a generalized version of the mixing length theory to compute red giant models and we introduce fingering convection using the BGS prescription. Results. The results show that, although the fingering zone now reaches the outer dynamical convective zone, the efficiency of the mixing is not enough to account for the observations. The fingering mixing coefficient should be increased by two orders of magnitude for the needed surface abundances to be reached. Conclusions. We confirm that fingering convection cannot be the mixing process needed to account for surface abundances in red giant branch stars. Instituto de Astrofísica de La Plata |
| Databáze: | OpenAIRE |
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