1122 Hz rotation of XTE J1739-285 as a probe of quark matter in the interior of the neutron star

TL;DR

The paper suggests that the extremely rapid 1122Hz rotation of XTE J1739-285 can be used to probe the presence of quark matter inside neutron stars, indicating that submillisecond pulsars may reveal quark matter cores.

Contribution

It introduces a method to constrain neutron star composition using rotation frequency and gravitational wave instability analysis, proposing that such rapid pulsars could contain quark matter.

Findings

XTE J1739-285 likely contains a quark or hybrid star core.

Stellar radii constrained to 9-12 km, masses to 1.2-2.0 solar masses.

Rapid rotation frequency limits suggest quark matter presence.

Abstract

The recent discovery of burst oscillation at 1122Hz in the X-ray transient XTE J1739-285 supports the suggestion that it contains a submillisecond pulsar. In our estimations of the enormous dissipation effect in the transition boundary layer between quark matter core and hadron matter envelope, combing the viscosities of bulk mater in previous works, we show that XTE J1739-285 can be uniquely restricted to a quark star masquerading as a neutron star (hybrid star) that contains a pure quark matter or mixed quark-hadron matter core from minimizing gravitational wave radiation (r-mode) instability and Keplerian motion constraints at 1122Hz level through a three-parameters image. Such constraints allow the stellar radii in the range $9{\rm km}\leq R\leq 12{\rm km}$ and the stellar masses in the range $1.2M_\odot\leq M\leq 2.0M_\odot$. It perhaps implies that submillisecond pulsars are just probes of quark matter.