[Mesa-users] New to MESA need a bit of understanding

[Rob Farmer]

Hi,

First you'll want to turn of use_gr_factors at least till after the pre-ms
(and honestly you only really need them for NS models). If you simply want
a super massive star (how massive?) you can just change the initial mass
and mesa will adjust the starting mass for you and it can do this more
computationally efficiently than you could do manually with the mass_change
option. Otherwise if you care about how the mass is being accreted, then
there are many many timestep controls in mesa. The inlist you provides a
very basic set of controls, you may find help in the accreted_material_j
and accretion_with_diffusion test cases for controls that help you when
accreting material.

Also your accretion rate 10^-3 msun/yr which is numerically difficult to
handle, you may find more success with a lower accretion rate.

Rob


On Mon, 12 Aug 2019 at 16:26, Nicholas Herrington via Mesa-users <
mesa-users at lists.mesastar.org> wrote:

> Hi,
>
> Im trying to use the create pre main sequence model along with accretion
> controls to take a star and make it super massive. Im using specific
> accretion rates in my runs and my issue occurs with each accretion rate.
> Whenever I initiate the run, the star accretes matter until a certain mass
> (different for each rate) until it stops and prints min timestep error. If
> I reduce the min timestep in controls it gets to the same mass as before
> but runs for longer on that mass, without accreting any futher, then
> finishes with the same error message (even at very small min timestep
> values). Ive tried to set the max mass to no limit in the controls but this
> hasnt helped either.
>
> I am not sure how the timestep works with this model and why it accretes
> to a specific mass everytime reguardless of what time controls I add to the
> inlist. If anyone could explain or help me understand what I am doing
> wrong, that would be much appreciated.
>
> Thanks
> Nick
>
> OS: Linux distro, Pop OS
> MESA-r17701
> SDK: I downloaded the may 3 2019 version
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
>
>
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