Considerations on the Role of Fall-Back Discs in the Final Stages of the Common Envelope Binary Interaction

Understand

The common envelope interaction is thought to be the gateway to all evolved compact binaries and mergers.

• Hydrodynamic simulations of the common envelope interaction between giant stars and their companions are restricted to the dynamical, fast, in-spiral phase.
• They find that the giant envelope is lifted during this phase, but remains mostly bound to the system.
• At the same time, the orbital separation is greatly reduced, but in most simulations it levels off? at values larger than measured from observations.