Heavy element nucleosynthesis in rotating proto-magnetar winds
Tejas Prasanna, Matthew S. B. Coleman, Todd A. Thompson, Brian D. Metzger, Anirudh Patel, Bradley S. Meyer
arXiv:2507.01094v1 Announce Type: new
Abstract: The astrophysical origin of elements synthesized through the rapid neutron capture process ($r-$process) is a long standing mystery. The hot and dense environments of core-collapse supernovae have been suggested as potential $r-$process sites, particularly the neutrino-driven wind from the newly-born protoneutron star (PNS). Wind models that neglect the potential effects of strong magnetic fields and/or rapid rotation of the PNS typically fail to achieve the necessary conditions for production of the third $r-$process peak, but robustly produce a limited or weak $r-$process for neutron-rich winds. Axisymmetric magnetohydrodynamic simulations of rotating and non-rotating PNS winds with magnetar-strength fields reveal that high entropy material is quasi-periodically ejected from the equatorial closed zone of the PNS magnetosphere. Here, we post-process tracer particle trajectories from these simulations using a nuclear reaction network in order to explore the resulting nucleosynthesis across a range of PNS magnetic field strengths, rotation rates, and neutrino luminosities (cooling phase after core-bounce). We find that a robust $r-$process up to and beyond the third peak is generic to magnetar birth, even for magnetic fields as weak as $sim 5times 10^{14}$ G. Depending on the distribution of magnetic field strengths and rotation at birth, we estimate that magnetized PNS winds could account for $sim 5-100%$ of the Galactic $r-$process inventory, extending up to the third peak. The robust $r-$process in our calculations is accompanied by overproduction of elements with mass number $rm Alesssim 120$ compared to the Solar abundances. We also find that $^{92}rm Mo$ (a $p-$isotope) is produced in significant quantities in neutron-rich winds.arXiv:2507.01094v1 Announce Type: new
Abstract: The astrophysical origin of elements synthesized through the rapid neutron capture process ($r-$process) is a long standing mystery. The hot and dense environments of core-collapse supernovae have been suggested as potential $r-$process sites, particularly the neutrino-driven wind from the newly-born protoneutron star (PNS). Wind models that neglect the potential effects of strong magnetic fields and/or rapid rotation of the PNS typically fail to achieve the necessary conditions for production of the third $r-$process peak, but robustly produce a limited or weak $r-$process for neutron-rich winds. Axisymmetric magnetohydrodynamic simulations of rotating and non-rotating PNS winds with magnetar-strength fields reveal that high entropy material is quasi-periodically ejected from the equatorial closed zone of the PNS magnetosphere. Here, we post-process tracer particle trajectories from these simulations using a nuclear reaction network in order to explore the resulting nucleosynthesis across a range of PNS magnetic field strengths, rotation rates, and neutrino luminosities (cooling phase after core-bounce). We find that a robust $r-$process up to and beyond the third peak is generic to magnetar birth, even for magnetic fields as weak as $sim 5times 10^{14}$ G. Depending on the distribution of magnetic field strengths and rotation at birth, we estimate that magnetized PNS winds could account for $sim 5-100%$ of the Galactic $r-$process inventory, extending up to the third peak. The robust $r-$process in our calculations is accompanied by overproduction of elements with mass number $rm Alesssim 120$ compared to the Solar abundances. We also find that $^{92}rm Mo$ (a $p-$isotope) is produced in significant quantities in neutron-rich winds.