Speaker
Description
Many binary population-synthesis (BPS) codes have been developed over the last few decades to evolve binary stars throughout their entire evolutionary history. BPS codes are extremely useful for investigating astrophysical processes we observe in the universe such as supernovae, x-ray binaries, generation of r-process elements, and gravitational-wave populations. However, many current BPS codes, such as COSMIC, rely on antiquated single-star evolutionary tracks and coarse prescriptions for binary physics. Newer BPS codes, such as POSYDON, instead use MESA binary sequences that self-consistently evolve each star's internal structure along with the binary's orbit. However, these BPS codes are computationally expensive to create and therefore are limited in their ability to explore uncertainties in the physics of binary evolution. In this work, we generate populations evolved from the same initial binary star population using three BPS codes used in the community – COSMIC with standard single-star evolutionary tracks, COSMIC updated with MESA single-star tracks, and POSYDON, which uses full MESA binary sequences – to determine the robustness of population predictions across different simulation methods. Using compact binary mergers as a test case, we find stark differences in the rates, properties, formation pathways, and progenitors.
