Friday, April 05, 2024 at 12:15 pm

JILA Foothills Room

Shelley Cheng, Harvard University

"A Model for Eruptive Mass Loss in Massive Stars"

Abstract:

Eruptive mass loss in massive stars is observed to occur, but the mechanism(s) are not yet well-understood. One proposed physical explanation is that eruptive mass loss may be due to opacity peaks in the envelope of evolved massive stars that cause the star to locally exceed the Eddington limit. Here, we present a model that estimates upper limits of eruptive mass loss rates using MESA for stars with masses between 10 − 100 solar masses at solar and SMC metallicities. Our model applies a physically-motivated energy argument to the envelope of massive stars to estimate eruptive mass loss by locating regions where the energy associated with locally super-Eddington luminosity exceed the binding energy of the overlaying envelope. We find that eruptive mass loss of up to 4 x 10^(-2) solar masses/year is driven by the Helium opacity peak and occurs in a vertical band on the HR diagram between 3.5 K < log(T_eff ) < 4.0 K. This predicted eruptive mass loss prevents stars of initial masses > 20 solar masses from evolving to become red supergiants, offering a possible explanation for the observed lack of red supergiants in that mass regime.

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