[mesa-users] Stellar rotation and wind mass loss

[Bill Paxton]

Hi Ale,

First, thank you for your replies to mesa-users -- it is a big help to have involvement from people other than the developers!

Concerning you questions, are you using the test_suite/rlo code as a start?  If not, you should!

It includes magnetic braking using the formula from Rappaport, Verbunt, and Joss.  apj, 275, 713-731. 1983

It doesn't include enhanced winds caused by tidal synchronization, 
but the hooks are there to do it if you have a way to compute
the enhancement (is it really that significant?  are you getting close to rotational breakup?)

I can confirm that rotation is not in the currently released mesa. 
But I'm working on it!!!!  Hopefully we'll have an "alpha" release soon,
and then we'll need help with testing.  Perhaps as a potential user,
you'd be willing to help with the testing?  That would be great.

For you last question about doing a grid of binaries, you'll need to do
a driver that selects the initial orbital period, donor and accretor mass,
but the actual evolution of the case can be done using something closely
based on the test_suite/rlo code.

Cheers,
Bill




On Dec 3, 2010, at 11:30 AM, Alessandro Patruno wrote:

> Dear MESA developers, 
> 
> I am trying to simulate a set of binaries with a low mass donor star (typically below 1 Msun)
> with short orbital period (typically below ~1 day). 
> 
> In my simulations I need to include a wind mass loss recipe, and I'm using the de Jager ones. 
> >From a theoretical point of view, if I use a star of, say, 1 Msun, then this will have a rotational 
> period of about 1 month, like our Sun. Tidal synchronization however will shortly bring the stellar
> rotation to be the same as the orbital period, and therefore much faster than our Sun. 
> In this case I would expect a very large increase in the wind mass loss rate. 
> I am not sure whether these aspects are included in the code, from a quick inspection I couldn't find
> anything like this, but only the possibility of setting the "eta" value for the wind of non-rotating and rotating models. 
> Can you please confirm that the rotation and its evolution (and the subsequent effect on the wind loss)
> is not included as a feature of MESA ? 
> 
> Also, in the binary evolution I can't find magnetic braking, but only the GW angular momentum loss. 
> Is this also not yet included in the code ? 
> 
> On a separate note, I am planning to write a quick update for the MESA code to include the possibility of
> evolving a grid of binaries with variable initial orbital period, donor and accretor mass. 
> Since I'm not a Fortran programmer as good as you are, is some of you available to give me some help in the next
> days ?  Who should I contact ? 
> 
> Many thanks !
> 
> Ale
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