Comment on "Three-dimensional hydrodynamic simulations of the combustion of a neutron star into a quark star"

TL;DR

This paper comments on previous simulations of neutron star to strange star conversion, highlighting that such conversions are only relevant for low-mass neutron stars due to stability constraints, and discusses the implications for astrophysical coexistence.

Contribution

It clarifies the parameter space where neutron stars convert to strange stars, emphasizing the stability conditions and their astrophysical implications.

Findings

Conversion occurs only for low-mass neutron stars.

Massive neutron stars remain stable and do not convert.

Coexistence of neutron stars and strange stars depends on mass stability.

Abstract

If strange matter is absolutely stable, the ordinary nuclei decay to strangelets, while neutron stars convert into strange stars. Lifetimes of the ordinary nuclei are constrained experimentally to be above $\sim 10^{33}$ years, while lifetimes of the metastable neutron stars depend on the neutron star masses and can exceed the age of the Universe. As a consequence, the neutron stars and the strange stars can coexist in the Universe. We point out that numerical simulations of the conversion of neutron stars to strange stars, performed by M. Herzog and F. K. Roepke in Phys. Rev. D 84, 083002 (2011) [arXiv:1109.0539], are focused on a region in the parameter space of strange matter, in which low-mass neutron stars and strange stars are coexistent, whereas massive neutron stars are unstable and short lived on an astronomical timescale.