Combustion gasdynamics of the neutron $\to$ strange matter conversion: towards an assessment of realistic scenarios

TL;DR

This paper investigates the complex combustion process of neutron to strange matter conversion in dense stars, analyzing instabilities and regimes that influence the conversion speed and potential for detonation, with implications for astrophysical phenomena.

Contribution

It provides a detailed analysis of flame instabilities and regimes in neutron star conversion, highlighting the likelihood of turbulent or distributed burning and the potential for detonation.

Findings

Conversion velocity exceeds laminar flame speed by several orders of magnitude.

The burning occurs in turbulent or distributed regimes, not in laminar conditions.

A transition to detonation is plausible but requires further numerical simulation.

Abstract

A variety of descriptions of the conversion of a neutron into a strange star have appeared in the literature over the years. Generally speaking, these works treat the process as a mere phase transition or ignore everything but microscopic kinetics, attempting to pin down the speed of the conversion and its consequences. We revisit in this work the propagation of the hypothetical "combustion" n $\to$ SQM in a dense stellar environment. We address in detail the instabilities affecting the flame and present new results of application to the turbulent regime. The acceleration of the flame, the possible transition to the distributed regime and further deflagration-to-detonation mechanism are addressed. As a general result, we conclude that the burning happens in (at least) either the turbulent Rayleigh-Taylor or the distributed regime. In both cases the velocity of the conversion of the star is several orders of magnitude larger than vlam, making the latter irrelevant in practice for this problem. A transition to a detonation is by no means excluded, actually it seems to be favored by the physical setting, but a definitive answer would need a full numerical simulation.