[mesa-users] Low mass thermal pulses

[Michael Medford]

Thanks Matt! I'll give those various wind schemes a shot and see if they
sufficiently reduce the mass to jump beyond the thermal pulses. If I happen
upon any interesting results I'll be sure to bring them back to the mailing
list.

All the best,
~Michael

On Thu, Nov 13, 2014 at 12:58 PM, Matteo Cantiello <cantiel at kitp.ucsb.edu>
wrote:

> Hi Michael,
> this is notoriously a tricky evolutionary stage.
> The details of how a star gets rid of its envelope and transits to the
> cooling WD stage are not well understood.
> A possible approach is to increase the massloss (a motivation being that
> the thermal pulses help to remove material from the star).
> A recipe often used is the Bloecker (1995) wind, including its efficiency
> parameter (eta).
> I suggest you start looking at the test_suite agb_to_wd
> Let us know how it goes,
> cheers
>
> -M
>
>
>
> On Nov 13, 2014, at 10:49 AM, Michael Medford wrote:
>
> > Hello everyone,
> >
> > I have been evolving stars in the 4-7 solar mass range and have found
> that I am unable to get evolution past thermal pulses along the AGB. Even
> after letting the code run for long periods of time, the star seems unable
> to get past this pulses and move onto a WD. Has anyone had experience
> dealing with these thermal pulses before?
> >
> > I am running the following &controls:
> > initial_mass = 4 (or 7)
> > initial_z = 0.02
> > initial_y = 0.28
> >
> > mixing_length_alpha = 2
> >
> > mass_for_overshoot_full_on = 0 ! begin overshoot in Msun
> > mass_for_overshoot_full_off = 4 ! end overshoot in Msun
> >
> > overshoot_f_above_nonburn = 0.0016
> > overshoot_f_below_nonburn = 0.0016
> > overshoot_f_above_burn_h = 0.0016
> > overshoot_f_below_burn_h = 0.0016
> > overshoot_f_above_burn_he = 0.0016
> > overshoot_f_below_burn_he = 0.0016
> > overshoot_f_above_burn_z = 0.0016
> > overshoot_f_below_burn_z = 0.0016
> >
> > I have also attached the relevant inlist files, as well as some history
> profiles demonstrating the thermal pulses. As you can see the
> radius/luminosity of the star seems to be only slightly increasing over
> time as the star attempts to climb the AGB.
> >
> > Thanks for any help you can offer!
> > ~Michael Medford
> >
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-- 
Michael S. Medford
Northwestern University, Class of 2011
www.MichaelMedford.com
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