Neutron stars from young nearby associations the origin of RXJ1605.3+3249

TL;DR

This study traces the origins of the neutron star RXJ1605.3+3249 to nearby stellar associations and identifies potential supernova remnants and companion stars, providing insights into neutron star formation and local supernova history.

Contribution

It presents a method to identify neutron star birthplaces by combining stellar association data, runaway star analysis, and gamma-ray isotope observations, revealing specific origins for RXJ1605.3+3249.

Findings

RXJ1605.3+3249 likely born 0.45 Myr ago in Corona-Australis or Octans associations

Possible former companions HIP 68228 and HIP 89394 identified as runaway stars

Evidence of recent supernova activity from gamma-ray emission of 26Al

Abstract

Many neutron stars (NSs) and runaway stars apparently come from the same regions on the sky. This suggests that they share the same birth places, namely associations and clusters of young massive stars. To identify NS birth places, we attempt to and NS-runaway pairs that could be former companions that were disrupted in a supernova (SN). The remains of recent (<few Myr) nearby (< 150 pc) SNe should still be identifiable by observing the emission of rare radioisotopes such as 26Al and 60Fe that can also be used as additional indicators to confirm a possible SN event. We investigated the origin of the isolated NS RXJ1605.3+3249 and found that it was probably born ~100 pc far from Earth 0.45 Myr ago in the extended Corona-Australis or Octans associations, or in Sco OB4 ~1 kpc 3.5 Myr ago. A SN in Octans is supported by the identification of one to two possible former companions the runaway stars HIP 68228 and HIP 89394, as well as the appearance of a feature in the gamma ray emission from 26Al decay at the predicted SN place. Both, the progenitor masses estimated by comparison with theoretical 26Al yields as well as derived from the life time of the progenitor star, are found to be ~11MSun.