Fast rotation of neutron stars and equation of state of dense matter

TL;DR

This paper investigates how the equation of state of dense matter influences the maximum rotation rate and stability of neutron stars, especially those spinning at submillisecond periods, using recent observational data.

Contribution

It analyzes the impact of the dense matter EOS on the spin-up process and stability of rapidly rotating neutron stars, incorporating recent observational constraints.

Findings

Rotation significantly affects neutron star structure at submillisecond periods.

EOS determines the maximum achievable spin rate before instability.

Observational data constrains the EOS and neutron star properties.

Abstract

Fast rotation of compact stars (at submillisecond period) and, in particular, their stability, are sensitive to the equation of state (EOS) of dense matter. Recent observations of XTE J1739-285 suggest that it contains a neutron star rotating at 1122 Hz (Kaaret et al. 2007). At such rotational frequency the effects of rotation on star's structure are significant. We study the interplay of fast rotation, EOS and gravitational mass of a submillisecond pulsar. We discuss the EOS dependence of spin-up to a submillisecond period, via mass accretion from a disk in a low-mass X-ray binary.