Crust Glass Formation Reveals the Neutron Star Birth Properties in IGR J17480-2446
Phys. Rev. Lett. 137, 031402 – Published 16 July, 2026
DOI: https://doi.org/10.1103/xxb4-7zc8
Abstract
IGR J17480-2446 is a low-mass x-ray binary, harboring an exceptional accreting pulsar (a neutron star) with an unusual spin frequency of 11 Hz and a very slow postoutburst crust cooling. The former may imply that it is observed at an early stage of recycling, while the latter was shown to indicate the presence in the outer crust of a low thermal conductivity layer, possibly made of glass. Here we argue that the glass layer formation is a natural result of accretion induced failure of pristine cold crystalline crust. This allows us to determine the mass of the accreted material as , confirming a very early accretion stage for this neutron star. An analysis of the spin and thermal state reveals a peculiar set of neutron star birth properties which is commonly associated with “recycled” neutron stars, i.e., those that have been experiencing prolonged periods of accretion from a companion. We speculate that such birth properties may represent the outcome of neutron star formation in an electron-capture supernova.
