Magnetized White Dwarf Collapse Identified as Source of Heavy Elements and Kilonova Signals
Researchers present the first complete simulation of how magnetized white dwarfs collapsing under accretion can produce observable kilonova signatures and heavy elements through r-process nucleosynthesis. The study combines advanced magnetohydrodynamic simulations with radiation modeling and shows that strong magnetic fields eject neutron-rich material capable of creating lanthanide-rich kilonovas. The findings suggest magnetized white dwarf collapse is a viable mechanism for producing heavy elements like gold and could explain certain gamma-ray burst observations.
A new theoretical study presents end-to-end simulations of accretion-induced collapse (AIC) in magnetized white dwarfs, connecting the physics to observable kilonova signatures. Using 2D general-relativistic neutrino-magnetohydrodynamic simulations followed by detailed radiation transfer calculations, the researchers show that strong magnetic fields fundamentally alter the collapse outcome compared to previous unmagnetized models. Rather than producing proton-rich ejecta dominated by nickel-56, magnetized collapse ejects approximately 0.2 solar masses of neutron-rich material with an electron fraction around 0.24, enabling robust r-process nucleosynthesis up to and beyond the third peak of the periodic table. The resulting kilonovas are lanthanide-rich and dominated by near-infrared emission, with synthetic light curves showing striking agreement with observations of AT 2023vfi/GRB 230307A without parameter tuning. These results establish magnetized AIC as a compelling progenitor candidate for long-duration gamma-ray bursts with associated kilonovas and a viable channel for heavy element production in the universe.
What's missing
The study does not discuss potential observational challenges in distinguishing magnetized AIC kilonovas from those produced by neutron star mergers, which are the currently favored r-process site. Additionally, the frequency and detectability of magnetized AIC events relative to other heavy element production mechanisms is not addressed.
What different sources said
- arXiv astro-phCenter
Collapse of Magnetized White Dwarfs as site of Heavy Element Formation and Kilonova Signal
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