The time-dependent Rayleigh–Taylor instability in interstellar shells and supershells, including the eROSITA bubbles

The Rayleigh–Taylor (RT) instability is omnipresent in the physics of inversely density-stratified fluids subject to effective gravitational acceleration. In astrophysics, a steep stratification of the ambient medium can fragment a bubble shell faster due to a strongly time-dependent RT instability, causing the classical constant gravity models to fail. We derive the time-dependent instability cri...