[Mesa-users] [EXT] Re: Mass loss in conservative mass transfer

[Neev Shah]

Hi Natasha,

Thank you, that solved my problem! Setting
use_radiation_corrected_transfer_rate = .false. made it fully conservative.

Best,
Neev Shah (he/him)
Astronomy PhD student
Steward Observatory
University of Arizona

On Mon, Sep 16, 2024 at 6:23 PM Natasha Ivanova <nata.ivanova at ualberta.ca>
wrote:

>
> *External Email*
> ------------------------------
> Hi,
>
> I also bumped into it at some point.
>
> Default MESA assumes that another star is a BH, so the accretion rate is
> corrected for radiation losses without you realizing that. Roughly 10% goes
> away.
>
> if you do
>
> use_radiation_corrected_transfer_rate = .fasle.
>
> I think it will conserve mass properly.
>
> Best
> Natasha
>
> On Mon, Sep 16, 2024 at 2:26 PM Neev Shah via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
>
>> Hi,
>>
>> I am trying to run fully conservative mass transfer using the template in
>> $MESA_DIR/binary/work (mesa version mesa-24.08.1). I believe the winds are
>> set to 0, and the mass transfer parameters are also set to 0. I have turned
>> off the eddington limit to allow for conservative mass transfer
>> (limit_retention_by_mdot_edd = .false.). Initially, I kept the secondary as
>> a point particle (evolve_both_stars = .false.) and it led to some mass loss
>> from the system during mass transfer (figures below where I can see that
>> dm2/dt is smaller than dm1/dt during mass transfer) and I am not sure why
>> that is happening.
>>
>> [image: image.png]
>> [image: image.png]
>>
>> I checked that by evolving the secondary as well (evolve_both_stars =
>> .true.), the mass loss disappears and the system is fully conservative
>> (figures below). The only difference between the 2 runs was that I changed
>> evolve_both_stars from .false. to .true.
>>
>> [image: image.png]
>> [image: image.png]
>>
>> Is there any reason for why there is mass loss when treating the
>> secondary as a point particle?
>>
>> I have attached my inlists in the tarball below. My system had a donor
>> mass of 15, accretor mass of 10, and an initial orbital period of 20 days.
>>
>> Thank you!
>>
>> Best,
>> Neev Shah (he/him)
>> Astronomy PhD student
>> Steward Observatory
>> University of Arizona
>> _______________________________________________
>> mesa-users at lists.mesastar.org
>> https://lists.mesastar.org/mailman/listinfo/mesa-users
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>>
>>
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