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

[Rob Farmer]

Please keep replies on list.

If you are going to make stars that massive them you will need a lot more
in you inlist. You'll need to worry about what's convection is doing
(whether you should use mlt++ or not), what the atmospheres doing etc.

 I suggest also looking at the inlist_massive_defaults for more options.

Rob


On Mon, 12 Aug 2019, 17:58 Nicholas Herrington, <
Nicholas.Herrington at myport.ac.uk> wrote:

> Hi Rob,
>
> Thanks for your reply. I am trying to take a 2 solar mass star and accrete
> matter at 10^-3 Msun/yr, then a 10 solar mass star at 1 Msun/yr. I’ve tried
> some of the time step controls but it seems to just stop at 2790Msun and
> 150Msun respectively no matter what I try. From the work I’m following with
> the initial conditions in the controls I’m trying to get the stars to reach
> 10^4 solar masses.
>
> Il give the controls a look and try using the accretion controls you sent.
>
> Thanks again for your help
> Nick
>
> On Mon, 12 Aug 2019 at 17:33, Rob Farmer <r.j.farmer at uva.nl> wrote:
>
>> 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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