The SyXB IGR J16194-2810 and Gaia NSs

The wide main sequence star + neutron star (NS) binaries recently discovered using Gaia astrometry will eventually evolve into symbiotic X-ray binaries (SyXB), rare systems in which the compact object companion accretes from the wind of an evolved red giant. To open a window on the future evolution of these Gaia NSs, I used optical follow-up observations of IGR J16194-2810, one of the few known SyXBs, to derive the orbital and stellar parameters of the red giant. From joint modeling of the ellipsoidal light curve, radial velocity curve, and red giant SED, I derived an orbital period of 192.73 days and dynamically confirmed the presence of a NS companion. Modules for Stellar Experiments in Stellar Astrophysics (MESA) models predict that the red giant will overflow its Roche lobe in several million years, and that the system will eventually end up as one of the longest-period white dwarf + millisecond pulsar binaries known. The system likely survived a common envelope phase with a large donor-to-accretor mass ratio before emerging in a wide orbit. Simulations show that the NS likely formed with a weak kick, as stronger kicks would have likely disrupted the binary.

Read more about this research project in the associated publication here.