English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Measuring the time evolution of the effective surface temperature of neutronstars can provide invaluable information on the properties of their densecores. Here, we report on a new Chandra observation of the transient neutronstar low-mass X-ray binary HETE J1900.1-2455, which was obtained ~2.5 yr afterthe end of its ~10-yr long accretion outburst. The source is barely detectedduring the observation, collecting only six net photons, all below 2 keV.Assuming that the spectrum is shaped as a neutron star atmosphere model weperform a statistical analysis to determine a 1-sigma confidence upper rangefor the neutron star temperature of ~30-39 eV (for an observer at infinity),depending on its mass, radius and distance. Given the heat injected into theneutron star during the accretion outburst, estimated from data provided byall-sky monitors, the inferred very low temperature suggests that either thecore has a very high heat capacity or undergoes very rapid neutrino cooling.While the present data do not allow us to disentangle these two possibilities,both suggest that a significant fraction of the dense core is notsuperfluid/superconductor. Our modeling of the thermal evolution of the neutronstar predicts that it may still cool further, down to a temperature of ~15 eV.Measuring such a low temperature with a future observation may provideconstraints on the fraction of baryons that is paired in the stellar core.

Constraining the properties of dense neutron star cores: The case of the low-mass X-ray binary HETE J1900.1-2455