Light clusters in the liquid proto-neutron star inner crust

TL;DR

This paper investigates the composition of the hot, liquid crust of proto-neutron stars, highlighting the importance of multi-component nuclear models over single-nucleus approaches, especially for helium cluster abundances.

Contribution

It introduces a self-consistent multi-component model for proto-neutron-star crusts, emphasizing the role of helium clusters and thermodynamic consistency.

Findings

Multi-component plasma predicts higher helium cluster abundances.

Differences between multi-component and single-nucleus models are significant.

Helium clusters dominate at higher temperatures in the crust.

Abstract

Being born hot from core-collapse supernova, the crust of the proto-neutron star is expected to be made of a Coulomb liquid and composed of an ensemble of different nuclear species. In this work, we study the beta-equilibrated proto-neutron-star crust in the liquid phase in a self-consistent multi-component approach, employing a compressible liquid-drop description of the ions including the ion centre-of-mass motion. Particular care is also devoted to the calculation of the rearrangement term, thus ensuring thermodynamic consistency. We compare the results of the multi-component plasma calculations with those obtained within a one-component (single-nucleus) approach, showing that important differences arise between the predictions of the two treatments. In particular, the abundances of helium clusters become important using a complete multi-component plasma approach, and eventually dominate the whole distribution at higher temperature in the crust.