[Mesa-users] Help regarding magnetic braking

[Evan Bauer]

Hi Abhijnan,

Here's a quote from the third MESA instrument paper that should explain what you're seeing:
It is normally assumed that once a star becomes fully convective, the dynamo process that regenerates the field will stop working or at least behave in a qualitatively different manner. Similarly, magnetic fields in stars with radiative envelopes are of a significantly different nature than those seen in stars with convective envelopes, and there is no simple way to predict even the presence of magnetism (Donati & Landstreet 2009). By default, MESAbinary only accounts for magnetic braking as long as the star being braked has a convective envelope and a radiative core, though the process might still operate outside of these conditions.

The binary control that governs this is
https://docs.mesastar.org/en/release-r23.05.1/reference/binary_controls.html#keep-mb-on <https://docs.mesastar.org/en/release-r23.05.1/reference/binary_controls.html#keep-mb-on>

Cheers,
Evan

> On Sep 7, 2023, at 8:30 PM, ABHIJNAN KAR 20064 <abhijnank20 at iiserbpr.ac.in> wrote:
> 
> Hi all,
> I am actually running the evolution of binary systems for various donor mass values. However, one thing I have noted is that for some donor mass values - 1.3Msun, 1.4Msun , effect of magnetic braking on accretion is same for both mb on and off. That is, we do see exactly a similar track of accretion(generally for the mb off case, we expect some intermediate drop in accretion when magnetic braking switches off due to star being convective, but in these cases, both cases have a drop). Is it some problem in MESA, or we are missing something? 
> Any help is appreciated. Inlists are attached herewith.
> 
> <inlist_project>
> <inlist1>
> Regards,
> Abhijnan Kar(He/his/him)
> BS-MS,IISER Berhampur
> 
> 
> 
> 
> 
> 
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