| Title: |
Comparison of the Core-Collapse Evolution of Two Nearly Equal Mass Progenitors |
| Authors: |
Bruenn, Stephen W., Sieverding, Andre, Lentz, Eric J., Sukhbold, Tuguldur, Hix, W. Raphael, Huk, Leah N., Harris, J. Austin, Messer, O. E. Bronson, Mezzacappa, Anthony |
| Source: |
ApJ, 2023, 497, 35 |
| Publication Year: |
2022 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Solar and Stellar Astrophysics |
| More Details: |
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.
Comment: 24 pages; Accepted for publication in ApJ |
| Document Type: |
Working Paper |
| DOI: |
10.3847/1538-4357/acbb65 |
| Access URL: |
http://arxiv.org/abs/2211.12675 |
| Accession Number: |
edsarx.2211.12675 |
| Database: |
arXiv |
