A solution to the tension of burning on neutron stars and nuclear physics

TL;DR

This paper introduces a comprehensive model that explains the complex burst behaviors observed in neutron stars by linking accretion disc structure to nuclear physics, resolving longstanding discrepancies between theory and observations.

Contribution

The authors develop a unified model that accounts for all observed neutron star burst phenomena by connecting accretion disc structure with nuclear ignition physics.

Findings

Reconstructed conditions on neutron star surfaces matching observed burst properties.

Identified the accretion disc structure as key to burst behavior.

Reconciled theoretical predictions with observational data.

Abstract

When neutron stars accrete matter from a companion star, this matter forms a disc around them and eventually falls on their surface. Here, the fuel can ignite into bright flashes called Type I bursts. Theoretical calculations based on state-of-the-art nuclear reactions are able to explain many features of the bursts. However, models predict that the bursts should cease at high accretion rates, whereas in many sources they disappear at much lower rates. Moreover, their recurrence times also show strong discrepancies with predictions. Although various solutions have been proposed, none can account for all the observational constraints. Here we describe a new model that explains all the contradictory behaviours within a single picture. We are able to reconstruct the conditions on the star surface that determine the burst properties by comparing data to new simulations. We find strong evidence that the physical mechanism driving the burst behaviour is the structure of the accretion disc in the regions closest to the star. This connection reconciles the puzzling burst phenomenology with nuclear physics and also opens a new window on the study of accretion processes around compact objects.