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The proximity to the Eddington luminosity has been attributed as the cause of several observed effects in massive stars. Computationally, if the luminosity carried through radiation exceeds the local Eddington luminosity in the low-density…

Solar and Stellar Astrophysics · Physics 2022-12-14 Poojan Agrawal , Simon Stevenson , Dorottya Szécsi , Jarrod Hurley

Semiconvection - mixing that occurs in regions that are stable when considering compositional gradients, but unstable when ignoring them - is shown to have the greatest potential impact on main sequence stars with masses in the range 1.2 -…

Solar and Stellar Astrophysics · Physics 2016-01-27 Kevin Moore , Pascale Garaud

Double-line eclipsing binaries (DLEBs) have been recently used to constrain the amount of central mixing as a function of stellar mass, with contrasting results. In this work, we reanalyze the DLEB sample by Claret & Torres, using a…

Solar and Stellar Astrophysics · Physics 2019-03-20 Guglielmo Costa , Léo Girardi , Alessandro Bressan , Paola Marigo , Thaíse S. Rodrigues , Yang Chen , Antonio Lanza , Paul Goudfrooij

Observations show an almost ubiquitous presence of extra mixing in low-mass upper giant branch stars. The most commonly invoked explanation for this is thermohaline mixing. One-dimensional stellar evolution models include various…

Solar and Stellar Astrophysics · Physics 2022-12-28 Adrian E. Fraser , Meridith Joyce , Evan H. Anders , Jamie Tayar , Matteo Cantiello

Overshooting from the convective cores of stars more massive than about 1.2 M(Sun) has a profound impact on their subsequent evolution. And yet, the formulation of the overshooting mechanism in current stellar evolution models has a free…

Solar and Stellar Astrophysics · Physics 2019-05-29 Antonio Claret , Guillermo Torres

We substantially update the capabilities of the open source software package Modules for Experiments in Stellar Astrophysics (MESA), and its one-dimensional stellar evolution module, MESA Star. Improvements in MESA Star's ability to model…

Our poor understanding of the boundaries of convective cores generates large uncertainties on the extent of these cores and thus on stellar ages. Our aim is to use asteroseismology to consistently measure the extent of convective cores in a…

Solar and Stellar Astrophysics · Physics 2016-04-20 S. Deheuvels , I. Brandão , V. Silva Aguirre , J. Ballot , E. Michel , M. S. Cunha , Y. Lebreton , T. Appourchaux

The main scope of this paper is to investigate the possible existence of a metallicity dependence of the overshooting from main sequence stars turbulent cores. We focus on objects with masses in the range ~2.5 Msol - ~25 Msol. Basically,…

Astrophysics · Physics 2009-11-07 D. Cordier , Y. Lebreton , M. -J. Goupil , T. Lejeune , J. -P. Beaulieu , F. Arenou

Convective boundary mixing (CBM) in the advanced evolutionary stages of massive stars is not well understood. Structural changes caused by convection have an impact on the evolution as well as the subsequent supernova, or lack thereof. The…

Solar and Stellar Astrophysics · Physics 2018-12-26 Austin Davis , Sam Jones , Falk Herwig

The physical parameters of the retired A star HD 185351 were analysed in great detail by Johnson et al. (2014) using interferometry, spectroscopy and asteroseismology. Results from all independent methods are consistent with HD 185351…

Core overshoot is a large source of uncertainty in constructing stellar models. Whether the amount of overshoot is constant or mass dependent is not completely known, even though models sometimes assume a mass-based trend. In this work we…

Solar and Stellar Astrophysics · Physics 2020-11-25 Lucas S. Viani , Sarbani Basu

In a robust statistical way, we quantify the uncertainty that affects the calibration of the overshooting efficiency parameter $\beta$ that is owing to the uncertainty on the observational data in double-lined eclipsing binary systems. We…

Solar and Stellar Astrophysics · Physics 2016-02-17 G. Valle , M. Dell'Omodarme , P. G. Prada Moroni , S. Degl'Innocenti

In this paper, four sets of evolutionary models are computed with different values of the mixing length parameter $\alpha_{\rm p}$ and the overshooting parameter $\delta_{\rm ov}$. The properties of the convective cores and the convective…

Solar and Stellar Astrophysics · Physics 2015-05-14 Jin Jie , Chunhua Zhu , Guoliang Lv

Stellar models typically use the mixing length approximation as a way to implement convection in a simplified manner. While conventionally the value of the mixing length parameter, $\alpha$, used is the solar calibrated value, many studies…

Solar and Stellar Astrophysics · Physics 2018-05-16 Lucas S. Viani , Sarbani Basu , Joel J. M. Ong , Ana Bonaca , William J. Chaplin

The bright, nearby binary $\alpha$ Centauri provides an excellent laboratory for testing stellar evolution models, as it is one of the few stellar systems for which we have high-precision classical (mass, radius, luminosity) and…

Solar and Stellar Astrophysics · Physics 2018-09-19 M. Joyce , B. Chaboyer

We discuss the effects of convective overshooting in the PMS evolution of intermediate mass stars, by analysing in detail the early evolution towards the main sequence of a 2 M_sun stellar model. These effects can be extremely important in…

Astrophysics · Physics 2009-11-11 J. P. Marques , M. J. P. F. G. Monteiro , J. Fernandes

We study prospects for seismic sounding the layer of a partial mixing above the convective core in main-sequence stars with masses in the 1.2 -- 1.9 solar mass range. There is an initial tendency to an increase of convective core mass in…

Astrophysics · Physics 2007-05-23 B. L. Popielski , W. A. Dziembowski

Results of evolutionary modelling of subdwarf B stars are presented. For the first time, we explore the core and near-core mixing in the subdwarf B stars using new algorithms available in the MESA code: the predictive mixing scheme and the…

Solar and Stellar Astrophysics · Physics 2021-04-21 J. Ostrowski , A. Baran , S. Sanjayan , S. K. Sahoo

In the overshoot mixing model with an exponentially decreasing diffusion coefficient, the initial value of the diffusion coefficient plays a crucial role. According to the turbulent convective mixing model, the characteristic length of…

Solar and Stellar Astrophysics · Physics 2023-08-09 Qian-Sheng Zhang , Li Yan , Wu Tao , Jiang Chen

The Humphreys-Davidson (HD) limit empirically defines a region of high luminosities (log L > 5.5) and low effective temperatures (T < 20kK) on the Hertzsprung-Russell Diagram in which hardly any supergiant stars are observed. Attempts to…

Solar and Stellar Astrophysics · Physics 2021-02-17 Avishai Gilkis , Tomer Shenar , Varsha Ramachandran , Adam S. Jermyn , Laurent Mahy , Lidia M. Oskinova , Iair Arcavi , Hugues Sana