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Comparison of the Core-Collapse Evolution of Two Nearly Equal Mass Progenitors
Comparison of the Core-Collapse Evolution of Two Nearly Equal Mass Progenitors by Stephen W. Bruen et al. on Wednesday 23 November
We compare the core-collapse evolution of a pair of 15.8 $M_\odot$ stars with
significantly different internal structures, a consequence of bimodal
variability exhibited by massive stars during their late evolutionary stages.
The 15.78 and 15.79 $M_\odot $ progenitors have core masses of 1.47 and 1.78
$M_\odot$ and compactness parameters $\xi_{1.75}$ of 0.302 and 0.604. The core
collapse simulations are carried out in 2D to nearly 3 s post-bounce and show
substantial differences in the times of shock revival and explosion energies.
The 15.78 $M_\odot$ model explodes promptly at 120 ms post-bounce when a strong
density decrement at the Si--Si/O shell interface encounters the stalled shock.
The 15.79 $M_\odot$ model, which lacks the density decrement, takes 100 ms
longer to explode but ultimately produces a more powerful explosion. Larger
mass accretion rate of the 15.79 $M_\odot$ model during the first 0.8 s
post-bounce results in larger $\nu_{e}$/$\bar \nu_{e}$ luminosities and rms
energies. The $\nu_{e}$/$\bar \nu_{e}$ luminosities and rms energies arising
from the inner core are also larger in the 15.79 $M_\odot$ model throughout due
to the larger negative temperature gradient of this core due to greater
adiabatic compression. Larger luminosities and rms energies in the 15.79
$M_\odot$ model and a flatter and higher density heating region, result in more
energy deposition behind the shock and more ejected matter with higher
enthalpy. We find the ejected $^{56}$Ni mass of the 15.79 $M_\odot$ model is
more than double that of the 15.78 $M_\odot$ model. Most of the ejecta in both
models is moderately proton-rich, though counterintuitively the highest
electron fraction ($Y_e=0.61$) ejecta in either model is in the less energetic
15.78 $M_\odot$ model while the lowest electron fraction ($Y_e=0.45$) ejecta in
either model is in the 15.79 $M_\odot$ model.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12675v1
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By Corentin CadiouComparison of the Core-Collapse Evolution of Two Nearly Equal Mass Progenitors by Stephen W. Bruen et al. on Wednesday 23 November
We compare the core-collapse evolution of a pair of 15.8 $M_\odot$ stars with
significantly different internal structures, a consequence of bimodal
variability exhibited by massive stars during their late evolutionary stages.
The 15.78 and 15.79 $M_\odot $ progenitors have core masses of 1.47 and 1.78
$M_\odot$ and compactness parameters $\xi_{1.75}$ of 0.302 and 0.604. The core
collapse simulations are carried out in 2D to nearly 3 s post-bounce and show
substantial differences in the times of shock revival and explosion energies.
The 15.78 $M_\odot$ model explodes promptly at 120 ms post-bounce when a strong
density decrement at the Si--Si/O shell interface encounters the stalled shock.
The 15.79 $M_\odot$ model, which lacks the density decrement, takes 100 ms
longer to explode but ultimately produces a more powerful explosion. Larger
mass accretion rate of the 15.79 $M_\odot$ model during the first 0.8 s
post-bounce results in larger $\nu_{e}$/$\bar \nu_{e}$ luminosities and rms
energies. The $\nu_{e}$/$\bar \nu_{e}$ luminosities and rms energies arising
from the inner core are also larger in the 15.79 $M_\odot$ model throughout due
to the larger negative temperature gradient of this core due to greater
adiabatic compression. Larger luminosities and rms energies in the 15.79
$M_\odot$ model and a flatter and higher density heating region, result in more
energy deposition behind the shock and more ejected matter with higher
enthalpy. We find the ejected $^{56}$Ni mass of the 15.79 $M_\odot$ model is
more than double that of the 15.78 $M_\odot$ model. Most of the ejecta in both
models is moderately proton-rich, though counterintuitively the highest
electron fraction ($Y_e=0.61$) ejecta in either model is in the less energetic
15.78 $M_\odot$ model while the lowest electron fraction ($Y_e=0.45$) ejecta in
either model is in the 15.79 $M_\odot$ model.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12675v1