[mesa-users] Angular momentum loss due to winds

[Pablo Marchant]

Hi Glenn-Michael, thanks for reporting this.

Version 9921 contains the fix you suggest, could you please verify it works
as you expect. Note that while changing this I noticed an additional error,
wind mass transfer is ignoring the Eddington limit. Depending on what
you're doing that could be an issue for you as well. Will try to fix it as
soon as I can.

Also, if you have simple examples that can be used to validate the
implementation of these processes, we could include them in the test_suite
such that they are automatically tested with each release.

Cheers

On Wed, Jul 12, 2017 at 4:41 AM, Glenn-Michael Oomen <
glennmichael.oomen at kuleuven.be> wrote:

> Note:
>
> Subtracting b% mdot_wind_transfer(b% d_i)​ should also do the trick.
> ------------------------------
> *Van:* Glenn-Michael Oomen
> *Verzonden:* woensdag 12 juli 2017 11:09
> *Aan:* mesa-users at lists.sourceforge.net
> *Onderwerp:* Angular momentum loss due to winds
>
>
> Hi Mesa,
>
>
> There might be a small problem with how the loss of angular momentum due
> to stellar winds is computed. It appears to me that b% mdot_system_wind is
> not actually the mass lost due to stellar winds from the system, but the total
> wind mass loss.
>
>
> So suppose I would for some reason impose a conservative wind mass
> transfer such that all the wind is transferred to the companion, then I
> would expect b% mdot_system_wind(b% d_i) to be zero, which is not the
> case. The bottom line is that this gives an overestimate for b% jdot_ml.
>
>
> The issue is in line 290 (and 293) in binary_evolve.f90, where b%
> mdot_system_wind appears to be defined simply as the wind mass loss of
> the star. I think that the whole equation should be multiplied by (1 - b%
> wind_xfer_fraction(s_i)) as to account for wind mass transfer to the
> companion and vice versa.
>
>
> Cheers,
>
> Glenn-Michael Oomen
>
>
>
>
>
>
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-- 
Pablo Marchant Campos
M.Sc on Astrophysics, Universidad Católica de Chile
PhD on Astrophysics, Argelander-Institut für Astronomie, Universität Bonn
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