English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

(abridged) The calculation of the thermal stratification in thesuperadiabatic layers of stellar models with convective envelopes is a longstanding problem of stellar astrophysics, and has a major impact on predictedobservational properties like radius and effective temperature. The MixingLength Theory, almost universally used to model the superadiabatic convectivelayers, contains effectively one free parameter to be calibrated --alpha(ml)--whose value controls the resulting effective temperature. Here we present thefirst self-consistent stellar evolution models calculated by employing theatmospheric temperature stratification, Rosseland opacities, and calibratedvariable alpha(ml) (dependent on effective temperature and surface gravity)from a large suite of three-dimensional radiation hydrodynamics simulations ofstellar convective envelopes and atmospheres for solar stellar composition(Trampedach et al. 2013). From our calculations (with the same composition ofthe radiation hydrodynamics simulations), we find that the effectivetemperatures of models with the hydro-calibrated variable alpha(ml) displayonly minor differences, by at most ~30-50 K, compared to models calculated atconstant solar alpha(ml). The depth of the convective regions is essentiallythe same in both cases. We have also analyzed the role played by thehydro-calibrated T(tau) relationships in determining the evolution of the modeleffective temperatures, when compared to alternative T(tau) relationships oftenused in stellar model computations. The choice of the T(tau) can have a largerimpact than the use of a variable alpha(ml) compared to a constant solar value.We found that the solar semi-empirical T(tau) by Vernazza et al. (1981)provides stellar model effective temperatures that agree quite well with theresults with the hydro-calibrated relationships.

Stellar models with mixing length and T(tau) relations calibrated on 3D convection simulations