[Mesa-users] Help regarding custom mesa run

Wed Dec 28 11:29:03 UTC 2022

Dear Abhijnan, Pulkit,

If I understand what you're trying to do, essentially you have a
relationship between the gravitational and baryonic mass of the neutron star
M_G = M_G(M_B)
such that as the neutron star accretes, you want its gravitational mass
(which is what the binary modules takes as the mass) to change according to
\dot{M}_G = (d M_G/d M_B) \dot{M}_B
where \dot{M}_B would be more or less the mass transfer rate that is given
by MESA. Is this what you're trying to do?

In such a case, this can be achieved using the option
`use_this_for_mdot_edd_eta`. This was mostly made for black hole
accretors that are expected to radiate a significant fraction \eta of the
accreted materials rest mass energy. From the documentation (
https://docs.mesastar.org/en/release-r22.11.1/reference/binary_controls.html#use-radiation-corrected-transfer-rate),
we have that with the option `use-radiation-corrected-transfer-rate` the
mass of the point mass changes as (you can ignore the BH notation in the
docs, MESA does not know what is the nature of the point mass)
delta_Mbh = (1-eta)*mass_transfer_rate*dt
By default MESA will compute eta assuming a BH accretor, but in your case
you could set it explicitly. If I understood what you're doing, then you
just need to set
eta = 1 - (d M_G/d M_B)
you can set the value of this option during each step of a run using
run_binary_extras, with the extras_binary_start_step subroutine.

Cheers

On Mon, Dec 26, 2022 at 4:57 PM Francis Timmes via Mesa-users <
mesa-users at lists.mesastar.org> wrote:

> > Also, we were wondering if there is a limit to the maximum number of
> steps apart from the physical conditions(which are eventually met) or some
> condition which sets such a limit?
>
> there is not a limit that i am aware of:
>
>
> https://docs.mesastar.org/en/release-r22.11.1/reference/controls.html#max-model-number
>
> for example, i've run jobs that have exceed 2 million timesteps.
>
> fxt
>
>
>
>
>
> > On Dec 25, 2022, at 11:41 PM, Pulkit Ojha via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
> >
> > Dear mesa-users,
> >
> > I'm Pulkit, working on the same problem along with Abhignan. As Dr. Evan
> had suggested, we also came to the conclusion that we can just modify our
> subroutine in binary_extras to reach our target.  Our essential target is
> to modify a few of the calculated parameters before using that as input for
> the next step. For instance, if our parameter of interest is mass transfer
> rate and we need to take square/multiple (just for example) of the
> calculated rate as input for our next step. We can just write this as an
> extra line in the subroutine which calculates the mass transfer rate and
> instruct mesa to use this subroutine. We just need to confirm, should we
> proceed with this?
> >
> > Also, we were wondering if there is a limit to the maximum number of
> steps apart from the physical conditions(which are eventually met) or some
> condition which sets such a limit?
> >
> > Shall be grateful for your help.
> >
> > Truly yours
> > Pulkit
> >
> >
> > On Thu, Dec 22, 2022, 10:51 AM ABHIJNAN KAR 20064 <
> abhijnank20 at iiserbpr.ac.in> wrote:
> > Hi,
> > I want to read the variables 'dot_Mmt' or accreted mass from the MESA
> output in each step,then take it in a formula to adjust for the difference
> between gravitational mass and total accreted mass.After that, the adjusted
> mass will again be taken as input in the next MESA step.This should go on
> till the total run is completed.This was my preliminary plan .Also for the
> change in the mass, other variables will change too but at first I was
> thinking to implement so as to check whether the code is working correctly
> or not.I am trying to implement the code in binary_extras as pointed out by
> Evan.
> >
> >
> >
> > On Wed, 21 Dec 2022, 19:17 Pablo Marchant, <pamarca at gmail.com> wrote:
> > Dear Abhijnan,
> >
> > it would be useful for you to be explicit about what variables you would
> be reading from the MESA model, and which input variables you would modify.
> When you were picturing doing this by stopping and rerunning a simulation,
> what was your precise plan? If you're still unfamiliar about binary
> modeling in general I would suggest you start up with a simpler example,
> such as the lab Evan points to, before doing more elaborate simulations.
> >
> >  Cheers
> >
> > On Tue, Dec 20, 2022 at 6:40 PM ABHIJNAN KAR 20064 <
> abhijnank20 at iiserbpr.ac.in> wrote:
> > Hi Evan,
> > Thanks for the response!
> > Yeah, I am trying to do it with help of extras routine.
> > However, I have one question in the custom code,for the output values of
> the desired variables/parameters at each step, should i write it like :
> call run_binary_extras(output variable, age_yr) ?
> > will this give an array which will change its value with run?
> > And at first I am declaring variables like
> > real :: output1, new_input
> >
> >> On 20-Dec-2022, at 12:31 AM, Evan Bauer <evan.bauer.astro at gmail.com>
> wrote:
> >>
> >> Hi Abhijnan,
> >>
> >> Yes, it should be possible to do what you describe with
> run_binary_extras. If you aren't already familiar with using
> run_star_extras and run_binary_extras, here's the place to start learning
> in the documentation:
> https://docs.mesastar.org/en/release-r22.11.1/using_mesa/extending_mesa.html
> >>
> >> For run_binary_extras specifically, Pablo's lab from this year's summer
> school has a lot of great material that should help you get a sense of how
> to use it: https://orlox.github.io/mesa2022_hmxb/
> >>
> >> Cheers,
> >> Evan
> >>
> >>> On Dec 15, 2022, at 11:50 AM, ABHIJNAN KAR 20064 <
> abhijnank20 at iiserbpr.ac.in> wrote:
> >>>
> >>> Hi Pablo,
> >>> Thanks for the reply!I want to take the output values of MESA run at
> each step, employ those values in formulae to adjust for difference between
> gravitational mass and baryonic mass(assuming M acc= delM g is not full
> expression: Mon. Not. R. Astron. Soc. 413, L47–L50 (2011)), then take the
> output values of the formulae and use it in again in next step of MESA
> run.Like this the loop will go on. Now, is it possible without having a
> driver code for the whole process?(just from run_binary_extras).
> >>>
> >>>> On 15-Dec-2022, at 7:36 PM, Pablo Marchant <pamarca at gmail.com> wrote:
> >>>>
> >>>> Dear Abhijnan,
> >>>>
> >>>> to help you it would be useful to know more precisely what you're
> trying to do. In particular, what parameters do you need to change, and on
> what output values do these depend? The use case you describe sounds like
> something that can be achieved inside a single run using run_binary_extras
> (without the need to stop and reload simulations), but without further
> details it is hard to know.
> >>>>
> >>>> Best,
> >>>>
> >>>> Pablo
> >>>>
> >>>> On Wed, Dec 14, 2022 at 5:34 PM ABHIJNAN KAR 20064 <
> abhijnank20 at iiserbpr.ac.in> wrote:
> >>>> Hi all,
> >>>> I am currently working the recent mesa version in the field of binary
> evolution.I am trying to model a binary system consisting of neutron star
> and a donor star and its orbital parameter. However, what I want to do is
> that I want to stop the MESA at every step of run binary evolution run and
> take the output of each step, calculate those outputs in some other
> formulas regarding some parameters and again start the mesa with the output
> values from the formulas as input for next step and so on. Can anyone
> please help in the software aspect i.e how to stop the mesa at every step
> automatically and extract the output values to be used in some other
> formulae?
> >>>> It would be extremely helpful!
> >>>> Regards,
> >>>> Abhijnan Kar(He/his/him)
> >>>> BS-MS,IISER Berhampur
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> mesa-users at lists.mesastar.org
> >>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
> >>>>
> >>>>
> >>>>
> >>>> --
> >>>> Pablo Marchant Campos
> >>>> M.Sc on Astrophysics, Universidad Católica de Chile
> >>>> PhD on Astrophysics, Argelander-Institut für Astronomie, Universität
> Bonn
> >>>
> >>> Regards,
> >>> Abhijnan Kar(He/his/him)
> >>> BS-MS,IISER Berhampur
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> mesa-users at lists.mesastar.org
> >>> https://lists.mesastar.org/mailman/listinfo/mesa-users
> >>>
> >>
> >
> > Regards,
> > Abhijnan Kar(He/his/him)
> > BS-MS,IISER Berhampur
> >
> >
> >
> >
> >
> >
> >
> >
> > --
> > Pablo Marchant Campos
> > M.Sc on Astrophysics, Universidad Católica de Chile
> > PhD on Astrophysics, Argelander-Institut für Astronomie, Universität Bonn
> > _______________________________________________
> > mesa-users at lists.mesastar.org
> > https://lists.mesastar.org/mailman/listinfo/mesa-users
> >
> > _______________________________________________
> > mesa-users at lists.mesastar.org
> > https://lists.mesastar.org/mailman/listinfo/mesa-users
> >
>
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
>
>

-- 
Pablo Marchant Campos
M.Sc on Astrophysics, Universidad Católica de Chile
PhD on Astrophysics, Argelander-Institut für Astronomie, Universität Bonn
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