Proto-neutron star evolution with improved charged-current neutrino–nucleon interactions

Abstract

We perform simulations of the Kelvin-Helmholtz cooling phase of proto-neutron stars with a new numerical code in spherical symmetry and using the quasi-static approximation. We use for the first time the full set of charged-current neutrino-nucleon reactions, including neutron decay and modified Urca processes, together with the energy-dependent numerical representation for the inclusion of nuclear correlations with random-phase approximation. Moreover, convective motions are taken into account within the mixing-length theory. As we vary the assumptions for computing neutrino-nucleon reaction rates, we show that the dominant effect on the cooling timescale, neutrino signal and composition of the neutrino-driven wind comes from the inclusion of convective motion. Computation of nuclear correlations within the random phase approximation, as compared to mean field approach, has a relatively small impact.

Three-dimensional General-relativistic Simulations of Neutrino-driven Winds from Rotating Proto-neutron Stars

“…Figure 4 (bottom row) shows that by t ∼ 100 ms, Y e,eq abs has settled close to a value of ∼0.35, with Y e approaching this value as well, from below. These Y e values are lower than predicted by detailed PNS cooling calculations at epochs of comparable neutrino luminosities to those of our solutions (e.g., Martínez-Pinedo et al 2012;Pascal et al 2022); this is not surprising because our initial conditions are not based on the self-consistent outcome of a successful supernova and because the decoupling region which determines the neutrino luminosities and energies is not well resolved (Figure 1).…”

“…As a consequence of this, as well as of our idealized initial temperature/Y e structure, the partitioning between ν e and e n ¯luminosities and their energies in our simulations do not match those predicted by supernova simulations, nor the resulting wind electron fractions Y e  Y e,eq abs (L , e e n n ¯, E , e e n n ¯). Specifically, our nonrotating wind solutions achieve values Y e ; 0.34 (Figure 4) significantly lower than those found by detailed PNS cooling calculations, Y e ≈ 0.45-0.55 (e.g., Roberts & Reddy 2017;Pascal et al 2022). Nevertheless, our simulations can still be used to explore the relative effects of rotation on Y e through a comparison to otherwise equivalent nonrotating models with similar neutrino emission properties.…”

“…The winds from very rapidly spinning PNS could therefore generate nucleosynthetic abundance patterns that are quantitatively distinct from those of slowly rotating PNS, even neglecting potential rotationinduced changes to the PNS cooling evolution. For example, if slowly rotating PNS winds achieve Y e  0.5-0.55 (e.g., Pascal et al 2022) and generate mostly iron group elements and p-nuclei via the rp-process and νp-process (e.g., Fröhlich et al 2006;Roberts et al 2010;Fischer et al 2010), rotating PNS winds could obtain Y e  0.5 and would instead synthesize neutron-rich LEPP or light r-process nuclei (e.g., Qian & Wasserburg 2007;Arcones & Montes 2011). 5.…”

“…events as sources of heavy r-process nuclei unless Y e = 0.4. Furthermore, if Y e > 0.5, as suggested by some recent cooling calculations of nonrotating PNS (e.g., Pascal et al 2022), then an r process will not be achieved for any value of η (however, see Meyer 2002 for an exception).…”

Delta-resonances and hyperons in proto-neutron stars and merger remnants

“…The formation of hot and neutrino-rich compact objects is predicted by numerical simulations of core-collapse supernova (SN) and BNS mergers. In the core-collapse supernova context, a hot proto-neutron star is formed during the contraction of the supernova progenitor and subsequent gravitational detachment of the remnant from the expanding ejecta [2][3][4][5][6][7][8][9][10]. A transient formation of dense hot matter arises in the case when the progenitor mass is large (typically tens of solar masses) and the matter collapses into a black hole [11][12][13][14].…”