The Production of Actinides in Neutron Star Mergers

TL;DR

This paper reviews how neutron star mergers produce actinides via the r-process, discussing nuclear physics, observational signatures, and implications for astrophysics and cosmochemistry.

Contribution

It summarizes recent research on actinide production in neutron star mergers, highlighting nuclear physics inputs and observational constraints.

Findings

Actinide production depends on specific nuclear physics conditions.

Future observations can probe actinide signatures in kilonovae and gamma rays.

Presence of actinides influences solar system radioactive element abundances.

Abstract

Although the multimessenger detection of the neutron star merger event GW170817 confirmed that mergers are promising sites producing the majority of nature's heavy elements via the rapid neutron-capture process ($r$-process), a number of issues related to the production of translead nuclei -- the actinides -- remain to be answered. In this short review paper, we summarize the general requirements for actinide production in $r$-process and the impact of nuclear physics inputs. We also discuss recent efforts addressing the actinide production in neutron star mergers from different perspectives, including signatures that may be probed by future kilonova and $\gamma$-ray observations, the abundance scattering in metal-poor stars, and constraints put by the presence of short-lived radioactive actinides in the Solar system.