Asymmetry of Shock Breakout in Geometrically Thick Disks

Determine whether a forward–backward asymmetry in the mass, energy, and luminosity of star–disk collision ejecta survives in a realistic, geometrically thick accretion disk, where shocked gas must traverse several scale heights before breakout.

Background

The simulations cannot measure the flux emerging from the disk side opposite to the stellar motion because the geometrically thick disk photosphere approaches the computational-domain boundary. Previous thin-disk simulations found substantial differences between forward and backward ejecta, and such asymmetry has been proposed to explain alternating strong and weak QPE flares or the detectability of only one flare per orbit.

The unresolved issue is whether comparable asymmetry persists when the shocked gas propagates through the extended atmosphere of a realistic, geometrically thick disk. Resolving both disk faces simultaneously would require simulations of a moving star in a spatially fixed disk.