[mesa-users] Thermal timescale mass-transfer

Jaime Villaseñor jaime.villasenor at postgrado.uv.cl
Fri Dec 20 14:05:01 EST 2013


Hi Pablo,  sorry for the poor redaction.

Jaime, I'm not sure what you mean with:
>
> "cataclysmic variables evolves in this way as it should with the same test
> "
>
> Are you saying you model a system where you evolve also the full structure
> of the WD and somehow get a different result? Or you mean that other
> published results say that and you're trying to reproduce them with MESA?
> If so, could you provide a reference?
>

I meant the second. When evolving pre-CVs with the "binary donor only"
test, I found results that are in agreement with published results, e.g.
Howell et al. 2001 (ApJ. 550, 897), Knigge et al. 2011 (ApJS, 194, 28).

" I would expect the system to evolve to shorter periods if it is in a
> synchronous orbit through angular momentum loss"
>
> Are you talking about magnetic braking here, which would take angular
> momentum from the rotation of the star, which would then take angular
> momentum from the orbit to go into synch? As far as I know, you can get
> both systems that will get significantly closer to each other, and others
> for which magnetic braking won't be strong enough, so they will just drift
> apart. What initial periods are you using?
>

Yes, I'm talking about magnetic braking taking away angular momentum from
the orbit of the binary. I'm using a 5 days initial orbital period, so I
thought that MB should efficiently reduce the orbit of the binary.

In CVs mass transfer is stable, so I want to see now how MESA deals with
thermal timescale mass-transfer. I've seen the code has convergence
problems with unstable mass-transfer, but that is another issue.

Best, Jaime.



2013/12/20 Pablo Marchant <pamarca at gmail.com>

> Jaime, I'm not sure what you mean with:
>
> "cataclysmic variables evolves in this way as it should with the same test
> "
>
> Are you saying you model a system where you evolve also the full structure
> of the WD and somehow get a different result? Or you mean that other
> published results say that and you're trying to reproduce them with MESA?
> If so, could you provide a reference?
>
> I also don't get what you say with:
>
> " I would expect the system to evolve to shorter periods if it is in a
> synchronous orbit through angular momentum loss"
>
> Are you talking about magnetic braking here, which would take angular
> momentum from the rotation of the star, which would then take angular
> momentum from the orbit to go into synch? As far as I know, you can get
> both systems that will get significantly closer to each other, and others
> for which magnetic braking won't be strong enough, so they will just drift
> apart. What initial periods are you using?
>
>
> On Thu, Dec 19, 2013 at 9:46 PM, Jaime Villaseñor <
> jaime.villasenor at postgrado.uv.cl> wrote:
>
>> Dear mesa users,
>>
>> I've been trying to reproduce the evolution of a binary system that
>> should enter into a thermal timescale mass-transfer phase with the "binary
>> donor only" test. I found that at some point after mass transfer starts
>> (around 5 Gyr), the orbital period is dramatically increased from the
>> initial 5 days to around 30 days. However, I would expect the system to
>> evolve to shorter periods if it is in a synchronous orbit through
>> angular momentum loss. I'm assuming this because cataclysmic variables
>> evolves in this way as it should with the same test.
>>
>> Any idea on what am I missing here?
>> I'm using mesa version 5595 and evolving a WD  of 0.8 solar masses and a
>> donor of 1.3 Msun.
>>
>> Thanks as usually for your valuable help.
>> Best, Jaime.
>>
>>
>> --
>> Jaime Villaseñor
>> Master's student in Astrophysics
>> Universidad de Valparaíso
>>
>>
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>
>
> --
> Pablo Marchant Campos
> M.Sc on Astrophysics, Universidad Católica de Chile
> PhD student, Argelander-Institut für Astronomie
>



-- 
Jaime Villaseñor
Master's student in Astrophysics
Universidad de Valparaíso
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