[Mesa-users] Setting H-envelope mass in subdwarfs

Kunal Deshmukh kunaldes225 at gmail.com
Tue Aug 9 20:35:51 UTC 2022

Thank you Heran, Evan.
I was indeed able to vary the envelope mass as I intended to. Thanks for
pointing out the He core boundary definition as well.

As a follow up question -
I used the make_sdb test which uses 1M_pre_ms_to_WD and results in an sdB
mass of about 0.47 Msun. To obtain higher mass sdBs (say 0.55 Msun), we
need to start with higher pre-MS masses (upwards of 3 Msun). What is the
correct way to go about this?

The simplest way I could think of was changing initial mass in
1M_pre_ms_to_WD from 1 Msun to 3 Msun. The numerous parameters in the
inlist however have been set for 1 Msun. Is there any prescribed way to
form high mass sdBs or will I have to change all the parameters according
to the initial mass for every case?

Finally, on a related note, how do we run a subset of parts in tests that
have multiple parts? (ex. run 1M_pre_ms_to_WD only till the
to_end_core_he_burn part)


On Mon, Aug 8, 2022 at 6:49 PM Evan Bauer <evan.bauer.astro at gmail.com>

> Hi Kunal,
> Yes, it looks like you've found the right control for retaining various H
> envelope masses in the make_sdb test case. I think that will do pretty much
> exactly what you expect, but feel free to let us know if you encounter
> unexpected behavior.
> The other thing to be aware of is the control that defines what
> constitutes "H envelope mass":
> https://docs.mesastar.org/en/release-r22.05.1/reference/controls.html#he-core-boundary-h1-fraction
> The H envelope in this case is everything above the He core boundary, and
> the definition of where the He core starts is set by that control.
> Cheers,
> Evan
> On Aug 2, 2022, at 10:38 PM, Kunal Deshmukh via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
> Hello,
> I am looking into the make_sdb test case with plans to work on sdB
> evolution. The inlist_make_sdb file by default includes the lines -
>      ! simulate common envelope event removing H envelope
>            relax_initial_mass_to_remove_H_env = .true.
>            lg_max_abs_mdot = -1
> I wish to retain H-envelopes of varying masses. I found the
> "extra_mass_retained_by_remove_H_env" command in the defaults file. Is this
> the right command to use or are there other ways to do it?
> Also, any other noteworthy precautions would also be appreciated.
> Thank you,
> Kunal Deshmukh
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
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