Title: Formation and Evolution of Thorne-Żytkow Objects
Speaker: Lauryn Williams (University of Washington)
Abstract:
Thorne-Zytkow Objects (TŻOs) represent a rare and enigmatic class of astrophysical objects, with a neutron star (NS) settled at the core of a large and diffuse envelope, yet their formation and long-term stability remain poorly understood. TŻOs are crucial for understanding the relationship between neutron stars and their companions while providing insights into stellar evolution and the dynamics of high-energy astrophysical environments. An under-explored aspect is the investigation into the dynamic stability of TŻOs formed through the scenario where a NS is “kicked” into its companion. My Ph.D. work has centered around this formation scenario, with each project deepening our understanding of the processes involved. My studies show the viability of TŻOs formed through this scenario and provide new perspectives on their evolution and observational parameters. My first 3D hydrodynamical simulations of neutron star-main sequence star mergers provide the bedrock for the two other studies by confirming that this formation scenario is a valid pathway to make dynamically stable TŻOs. Utilizing binary population synthesis codes, we’ve calculated an updated birth rate for dynamically formed TŻOs, providing a valuable comparison to previous estimates and improving observational efforts. Additionally, by inputting the results of the hydrodynamic simulations into a robust stellar evolution code, we will identify key observable characteristics that will strengthen the connection between theoretical studies and observational data. This research is a key step in refining this formation scenario, assessing TŻO prevalence, and understanding their role as terminal products of massive binary evolution.
