[Mesa-users] difficulty with custom mass loss

Aaron Dotter aaron.dotter at gmail.com
Mon Jul 15 22:29:27 EDT 2019

Hi Noah,

I've answered your questions below and, in the process, maybe found the
reason why your initial attempts weren't working.

s% star_mdot is the change in mass in Msun/year, used for reporting

s% mstar_dot is the quantity used in the code to affect the change in mass
but note that the units are g/s, not Msun/year.

The main reason why I wasn't using other_wind is that the mass loss which I
> wanted to model wasn't exclusively due to wind. If I were to use an
> other_wind hook, would it matter if the mass loss isn't actually wind?

No, it doesn't matter.

> Would I still modify s% star_mdot to set the mass loss rate, or is there
> another variable I should change?

You don't change s% star_mdot in your other wind routine.  Your other_wind
subroutine will set a variable w (see star/other/other_wind.f90), which is
returned to the calling routine set_mdot.

> If I wanted to set a custom wind for main sequence evolution would that be
> setting hot_wind_scheme = 'other' in the inlist?



> Thanks,
> Noah Tuchow
> Noah Tuchow Penn State University Department of Astronomy and Astrophysics 532C
> Davey Lab University Park, PA 16802
> On Mon, Jul 15, 2019 at 9:47 PM Aaron Dotter <aaron.dotter at gmail.com>
> wrote:
>> Hi Noah,
>> Just a suggestion: Have you tried using other_wind?  I've used that
>> successfully a number of times over the years.  It might be what you're
>> looking for rather than other_adjust_mdot.
>> Aaron
>> On Mon, Jul 15, 2019 at 9:34 PM TUCHOW, NOAH WOLFE <nxt5109 at psu.edu>
>> wrote:
>>> Hello everyone,
>>> I've been having a bit of difficulty trying to implement a custom mass
>>> loss rate for a main sequence star. I've started off simple, just slightly
>>> modifying the default work folder's inlists to make a 1 solar mass star
>>> losing mass with a mass loss rate given as a function of time. Since I want
>>> to specify a function for a custom mass loss mechanism, I have been trying
>>> to use the "other" hooks in run_star_extras to do so. However, I can't
>>> seem to get even the simplest example, a constant mass loss rate, working
>>> via run star extras. I made a simple subroutine called const_mdot, and
>>> I direct MESA to use it in extras_controls as an other_adjust_mdot. I
>>> am trying to set  s% star_mdot to be a value that I specify in the
>>> inlist, but, when I run MESA, I find that the mass of the star doesn't
>>> change at all.  I noticed that setting mass_change in the inlist
>>> controls does what I thought this would be doing, but I would eventually
>>> like to implement more complicated mass loss rates.
>>> Am I not implementing mass loss in the correct manner? Should I not put
>>> my mass loss subroutine as an other_adjust_mdot, or is s% star_mdot not
>>> the right quantity to be modifying? I know there is an other_wind option,
>>> but I'm dealing with mass loss from other sources such as CMEs not only
>>> wind. I've attached my inlists and run_star_extras.f  which I've been using
>>> in MESA r10398.  How does one specify a custom mass loss rate in MESA?
>>> Thanks,
>>> Noah Tuchow
>>> Noah Tuchow Penn State University Department of Astronomy and
>>> Astrophysics 532C Davey Lab University Park, PA 16802
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