Computer simulations of binary stars

Astrophysical processes within stars, such as mass transfer, mass loss, accretion, explosions, pulsations, turbulence, and mixing, cannot be directly observed, making computer simulations essential for advancing our understanding. Simulating binary stars is particularly challenging because these systems lack a useful symmetry that could simplify calculations, thus requiring high computational costs for accurate modeling. Additionally, events in binary systems span a vast range of physical and temporal scales and often involve complex interactions between subsonic and supersonic motions. These factors push current simulation methods in astrophysics to their technical limits.

In this project, we aim to enhance the numerical and astrophysical fidelity of computer simulations for binary systems comprising stars, neutron stars, and black holes. Based on the student’s interests, the project may involve developing new numerical techniques for binary simulations, optimizing existing codes for supercomputing architectures (including GPUs), or advancing the radiation/magneto-hydrodynamics codes used in our group. These developments will be applied to various binary systems, including common envelope evolution, tidally-deformed or mass-transferring stars, chemically homogeneous gravitational wave progenitors, classical novae, Type Ia supernovae, and circumbinary disks around binary supermassive black holes.

References:

[1] Calderón et al., 2021, Moving-mesh radiation-hydrodynamic simulations of wind-reprocessed transients, https://ui.adsabs.harvard.edu/abs/2021MNRAS.507.1092C/abstract
[2] Calderón et al., 2024, The effect of relativistic precession on light curves of tidal disruption events, https://ui.adsabs.harvard.edu/abs/2024MNRAS.528.2568C/abstract
[3] Gagnier & Pejcha, 2023, Post-dynamical inspiral phase of common envelope evolution. Binary orbit evolution and angular momentum transport, https://ui.adsabs.harvard.edu/abs/2023A%26A...674A.121G/abstract
[4] Gagnier & Pejcha, 2024, Post-dynamical inspiral phase of common envelope evolution. The role of magnetic fields, https://ui.adsabs.harvard.edu/abs/2024A%26A...683A...4G/abstract