The Energy Sharing Timescale in an Analytic Framework for Common Envelope Hydrodynamics

Abstract

We propose a new predictive theory for the analysis of common envelope (CE) events that incorporates the effects of relevant hydrodynamical processes into a simple analytical framework. We introduce the ejection and dynamical parameters ξ and β , which define whether envelope ejection is energetically or hydrodynamically favorable, respectively, during CE inspiral. When combined, these parameters offer a detailed narrative of how inspiral begins, proceeds, and ends that is consistent with preliminary comparisons to 3D hydrodynamical models. This physically motivated framework impacts predictions for CE outcomes, especially for systems that have energy excess, and offers promise as a potential alternative for the treatment of CEs in binary population synthesis.

Keywords

• Common envelope evolution
• Common envelope binary stars
• Binary stars
• Interacting binary stars
• Stellar evolution
• Stellar mergers