[Mesa-users] Schwarzschild and Ledoux Criteria

[Tomasz Plewa]

In theory, see for example Eq. 10 in Gabriel et al. (2014, AA, 569, A63), one should be able to obtain a series of Ledoux-based models by gradually increasing \alpha_sc from zero. All other parameters being equal, we expected that the first model in that Ledoux series to match the Schwarzschild model. But that did not seem the case as the two trajectories diverged forcing us to produce a Schwarzschild series separately.

Perhaps there exists a simple explanation for the observed lack of equivalence between the two models in the alpha_sc limit without getting buried in implementation details. That may not be possible, though, in which case a reference would be helpful.

Tomek
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On 7/20/19 12:59 PM, anne.thoul at uliege.be<mailto:anne.thoul at uliege.be> wrote:
Hi Antigoni

Could you give us more information about what you are doing?

Which version of MESA are you using?

There has been a lot of recent improvement done in MESA concerning the convective boundaries.
In the 4th instrument paper we introduced « predictive mixing » and in the fifth instrument paper we introduced « CPM » or « convective pre-mixing ».

Which of these prescriptions are you using?

I suggest you read those instrument papers (at least the sections about convective boundaries), and try to use one of these prescriptions for the convective boundaries. They improved considerably what the older versions of MESA did. Those prescriptions are not, however, the default at this point, so you have to specifically put the necessary controls in your inlists.

Those controls are explained in the instrument papers, and in the controls_default file.

If, however, your problems persist after having used the newer convective boundaries settings, please let us know and send us the inlist you use so that we can try to reproduce your problem.

Cheers

Anne




Le 20 juil. 2019 à 18:26, Antigoni Georgiadou via Mesa-users <mesa-users at lists.mesastar.org<mailto:mesa-users at lists.mesastar.org>> a écrit :

Hello,

I am working on stellar evolution applications with the MESA code and I wanted to ask about the way MESA operates for the Schwarzschild and Ledoux criteria.

For example, for a massive star of 30 Msun using the Schwarzschild criterion does not seem to be equivalent to using the Ledoux criterion with semiconvective parameter equal to 0.

I would really appreciate it if you can help me understanding this difference. I think it shouldn't appear any different.

Many thanks,

Antigoni Georgiadou
PhD Candidate
Department of Mathematics
Florida State University

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