# Quiescent Light Curve of Accreting Neutron Star MAXI J0556-332

## TL;DR

This study models the quiescent light curve of the accreting neutron star MAXI J0556-332, revealing that nuclear energy from the hot CNO cycle explains its observed cooling behavior, with implications for shallow crustal heating.

## Contribution

The paper demonstrates that the quiescent light curve can be explained by nuclear energy generation from the hot CNO cycle, considering outburst behavior effects.

## Key findings

- Hot CNO cycle explains the quiescent light curve.
- Shallow crustal heating Qshallow > 6 MeV per nucleon is needed.
- Outburst behavior influences crustal heating models.

## Abstract

MAXI J0556-332 is the hottest transient accreting neutron star at the beginning of its quiescence. A theoretical model with crustal heating indicates that an additional shallow heat source of Qshallow > 6 MeV per accreted nucleon is required in the shallow outer crust with respect to the deeper star crust by considering the observed decline in accretion rate at the end of outburst. However, the physical source of this shallow heating is still unclear. In the present investigation, we performed stellar evolutionary calculations, adopting the effects of outburst behavior of the accretion rate. As a consequence, we find that the quiescent light curve of MAXI J0556-332 can be well explained by the nuclear energy generation due to the hot CNO cycle.