[Mesa-users] difficulty with custom mass loss

[TUCHOW, NOAH WOLFE]

Great, thanks so much for your help.

Noah

Noah Tuchow
Penn State University
Department of Astronomy and Astrophysics
532C Davey Lab
University Park, PA 16802


On Mon, Jul 15, 2019 at 10:29 PM Aaron Dotter <aaron.dotter at gmail.com<mailto:aaron.dotter at gmail.com>> wrote:
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?


Yes.


Aaron



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<mailto: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<mailto: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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