Sep 27 – 30, 2021
Yerevan, Armenia
Etc/GMT+4 timezone

Constraining the properties of superdense matter with observations of low-mass X-ray binaries: the case of HETE J1900.1–2455

Sep 27, 2021, 3:00 PM
Yerevan, Armenia

Yerevan, Armenia

Department of Physics, Alex Manukyan str. 1, Yerevan, Armenia


Dr Mikhail Beznogov (National Institute for R&D in Physics and Nuclear Engineering (IFIN))


New observations of a transient neutron star in a low mass X-ray binary HETE J1900.1–2455 were carried out in 2018. Despite detecting only six net photons, it was still possible to infer the effective surface temperature of the star. It turned out to be quite low, ≈30 – 39 eV (for an observer at infinity) depending on the assumed mass, radius and distance to the star. Taking into account the amount of energy deposited during the ≈10 years accretion outburst as well as previous temperature measurements in 2016, these values can either indicate that the core has a very high heat capacity or that it undergoes rapid neutrino cooling. Unfortunately, current observational data does not allow us to distinguish between these two possibilities. However, both of them suggest that a significant fraction of the core is not superfluid (superconductor). Also, our modeling shows that the star can cool even further, up to the temperature of ≈15 eV. In this case future observations (that are already scheduled) might allow us to obtain constraints on the fraction of unpaired baryons in the core.

Primary authors

Dany Page (Universidad Nacional Autonoma de Mexico) nathalie degenaar (university of amsterdam) J. van den Eijnden (Anton Pannekoek Institute for Astronomy, University of Amsterdam) M. Reynolds (Department of Astronomy, University of Michigan) Dr Mikhail Beznogov (National Institute for R&D in Physics and Nuclear Engineering (IFIN)) Rudy Wijnands (University of Amsterdam)

Presentation materials