CSCDR seminar with Tia Martineau (University of New England), "Equation-of-State Dependence of Black Hole–Neutron Star Merger Ejecta: Implications for Heavy-Element Production”
Textiles 105A (CSCDR)
https://www.cscdr.umassd.edu/seminars
Abstract:
Identifying the astrophysical sources of the heaviest r-process elements requires connecting the conditions in neutron-rich outflows to their nucleosynthetic yields. Kilonova observations provide one avenue for investigating these sources, but the absence of a detectable kilonova does not necessarily exclude heavy-element production. Black hole-neutron star mergers near the tidal-disruption threshold offer a setting in which a remnant accretion disk may support a relativistic jet while the kilonova remains faint. I will present numerical-relativity simulations with the Spectral Einstein Code (SpEC), including Monte Carlo neutrino transport, of binaries in the mass regime of GW230529. Focusing on two nuclear equations of state, SFHo and DD2, I will compare configurations selected at comparable offsets above their respective predicted disruption thresholds. Although both produce small amounts of dynamical ejecta, their outflows differ in electron fraction, temperature, and angular distribution, providing distinct initial conditions for r-process nucleosynthesis. I will discuss the implications of these ejecta properties for r-process yields, their connection to ongoing collaborative nucleosynthesis calculations, and how these results motivate investigating spin misalignment and precession as additional influences on merger outflows