[Mesa-users] ?==?utf-8?q? Timestep issue at the He flash stage

[Dreau Guillaume]

Hello Bill,

Indeed, you are right. In my inlists, the timesteps were larger than those in the standard 1M_pre_ms_to_wd case because I was setting the option time_delta_coeff = 2d0 for some reasons. Unfortunately, when I keep the default value time_delta_coeff = 1d0 as in the standard case, the same issue occurs approximately 400 steps after the start from my start_he_core_flash.mod. In parallel, I also tried to run the standard 1M_pre_ms_to_wd case just by changing the option atm_T_tau_opacity = 'varying', from the PMS up to the RGB tip and I surprisingly get the same timestep stopping condition and I can't pass the helium flash stage. So I'm afraid that having the same timesteps as in the standard case may not be the solution.

Cheers,
Guillaume
*******************************************************************************************************************
Guillaume Dréau
PhD student 2nd year – Instructor
Speciality Stellar Physics
LESIA - Observatoire de Paris
Building 14, office 107
5 place Jules Janssen
92195 Meudon Cedex – France
http://www.lesia.obspm.fr/

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Le Vendredi, Février 05, 2021 20:23 CET, Bill Paxton <paxton at kitp.ucsb.edu> a écrit:
 
as you said, it takes your inlists about 100 steps for the end_core_he_burn part to get into trouble starting from your start_he_core_flash.mod. At that point, lg_L3a has reached 9.5, nearly the peak of the flash.

for comparison, the standard 1M_pre_ms_to_wd case takes over 400 steps to get a similar lg_L3a. It then continues happily though the flash.

so you need to see why your inlists are causing the code to take much larger timesteps than the standard inlists.

fix that so that the timesteps are similar, then see what happens and let us know.

cheers,
bill




 


 
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