Hydrodynamical Simulations of Circumbinary Accretion: Balance between Heating and Cooling

Understand

Hydrodynamical interaction in circumbinary discs (CBDs) plays a crucial role in various astrophysical systems, ranging from young stellar binaries to supermassive black hole binaries in galactic centers.

• Most previous simulations of binary-disc systems have adopted locally isothermal equation of state.
• In this study, we use the grid-based code $\texttt{Athena++}$ to conduct a suite of two-dimensional viscous hydrodynamical simulations of circumbinary accretion on a cartesian grid, resolving the central cavity of the binary.
• The gas thermodynamics is treated by thermal relaxation towards an equilibrium temperature (based on the constant$-\beta$ cooling ansatz, where $\beta$ is the cooling time in units of the local Keplerian time).