[mesa-users] Low mass thermal pulses

[Matteo Cantiello]

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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