[Mesa-users] Questions about convective mixing during a proton ingestion event (when the He-convective zone engulfs H material)

[Guo Li]

Hi all,
I hope this message finds you well.


I am simulating a 1Msun，[Fe/H]=-2.5 stellar evolution model based on the literature https://doi.org/10.1051/0004-6361/202040170. During the second Thermal Pulse (TP), the He-convective zone approaches the H-shell and engulfs H material, resulting in a proton ingestion event. After H is mixed into the He-convective zone, the literature indicates that the location with the highest H-burning energy production is in the middle of the He-convective zone, where energy accumulation leads to the splitting of the He-convective zone. However, in my results, the highest energy production occurs at the bottom of the convective zone, preventing the He-convective zone from splitting.

What could be the reason for this discrepancy? I suspect that the H profile gradient within the He-convective zone in my results is too small. Is this due to overly rapid convective mixing, or are there other reasons? The following figures show the mass fraction and energy profiles after the proton ingestion event.




I appreciate your assistance and look forward to your response.

Thank you!

Best regards,
Guo Li
National Astronomical observatories,CAS
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