Theory of stellar convection II: first stellar models

Abstract

We present here the first stellar models on the Hertzsprung-Russell diagram (HRD), in which convection is treated according to the novel scale-free convection theory (SFC theory) by Pasetto et al. (2014). The aim is to compare the results of the new theory with those from the classical, calibrated mixing-length (ML) theory to examine differences and similarities. We integrate the equations describing the structure of the atmosphere from the stellar surface down to a few percent of the stellar mass using both ML theory and SFC theory. The key temperature over pressure gradients, the energy fluxes, and the extension of the convective zones are compared in both theories. The analysis is first made for the Sun and then extended to other stars of different mass and evolutionary stage. The results are adequate: the SFC theory yields convective zones, temperature gradients of the ambient and of the convective element, and energy fluxes that are very similar to those derived from the "calibrated" MT theory for main sequence stars. We conclude that the old scale dependent ML theory can now be replaced with a self-consistent scale-free theory able to predict correct results, one which is simpler and more physically grounded than the ML theory. Fundamentally, the SFC theory offers a deeper insight of the underlying physics than numerical simulations.

Submitted to MNRAS, 22 pages, 10 figures

References in corpus (9)

• Improving PARSEC models for very low mass stars
• New PARSEC evolutionary tracks of massive stars at low metallicity: testing canonical stellar evolution in nearby star forming dwarf galaxies
• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• Structure and Evolution of Giant Cells in Global Models of Solar Convection
• The Stagger-grid: A grid of 3D stellar atmosphere models - III. The relation to mixing-length convection theory
• Rapidly Rotating Suns and Active Nests of Convection
• Beyond Mixing-length Theory: a step toward 321D
• Stellar models with mixing length and T(tau) relations calibrated on 3D convection simulations
• Theory of stellar convection: Removing the Mixing-Length Parameter

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