A semi-analytic approach to angular momentum transport in stellar radiative interiors - Astrophysics > Solar and Stellar AstrophysicsReportar como inadecuado




A semi-analytic approach to angular momentum transport in stellar radiative interiors - Astrophysics > Solar and Stellar Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We address the problem of angular momentum transport in stellar radiativeinteriors with a novel semi-analytic spectral technique, using an eigenfunctionseries expansion, that can be used to derive benchmark solutions inhydromagnetic regimes with very high Reynolds number 10^7 - 10^8. The errorarising from the truncation of the series is evaluated analytically. The mainsimplifying assumptions are the neglect of meridional circulation and ofnon-axisymmetric magnetic fields. The advantages of our approach are shown byapplying it to a spin-down model for a 1 M sun main-sequence star. Theevolution of the coupling between core and envelope is investigated fordifferent values of the viscosity and different geometries and values of thepoloidal field. We confirm that a viscosity enhancement by 10^4 with respect tothe molecular value is required to attain a rigid rotation in the core of theSun within its present age. We suggest that a quadrupolar poloidal field mayexplain the short coupling time-scale needed to model the observed rotationalevolution of fast rotators on the ZAMS, while a dipolar geometry is indicatedin the case of slow rotators. Our novel semi-analytic spectral method providesa conceptually simple and rigorous treatment of a classic MHD problem andallows us to explore the influence of various parameters on the rotationalhistory of radiative interiors.



Autor: F. Spada, A. C. Lanzafame, A. F. Lanza

Fuente: https://arxiv.org/



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