The Common Envelope Evolution Outcome. III. the Improvement of Stellar Binding Energy with the Envelope Residual

@misc{zhang2026common,
  title = {{The Common Envelope Evolution Outcome. III. the Improvement of Stellar Binding Energy with the Envelope Residual}},
  author = {Lifu Zhang and Hongwei Ge and Dylan Hebrail and Ross Church and Mingkuan Yang and Zhenwei Li and Hailiang Chen and Dengkai Jiang and Xuefei Chen and Zhanwen Han},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.24010},
  eprint = {2609.24010},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.24010},
}

TY  - UNPB
TI  - The Common Envelope Evolution Outcome. III. the Improvement of Stellar Binding Energy with the Envelope Residual
AU  - Lifu Zhang
AU  - Hongwei Ge
AU  - Dylan Hebrail
AU  - Ross Church
AU  - Mingkuan Yang
AU  - Zhenwei Li
AU  - Hailiang Chen
AU  - Dengkai Jiang
AU  - Xuefei Chen
AU  - Zhanwen Han
PY  - 2026
DA  - 2026/09/21
PB  - arXiv
DO  - 10.48550/arxiv.2609.24010
UR  - https://arxiv.org/abs/2609.24010
AB  - Common-envelope evolution (CEE) is a key process in the evolution of close binary systems. Many important astrophysical objects and evolutionary stages are closely related to CEE, including white dwarf binaries, hot subdwarfs, and gravitational wave mergers. In the standard energy formalism of CEE, the binding energy of the donor envelope plays a crucial role, as it directly affects the final orbital period after CEE and serves as a key physical parameter in binary population synthesis studies. However, the currently adopted binding energy suffers from large uncertainties, mainly because the envelope binding energy of giant-branch stars varies strongly near the helium-core boundary. In addition, the expansion of the star during CEE can also affect the binding energy. To address these issues, we introduce an improved binding energy for the envelope mass residual. Based on adiabatic mass loss models, we recalculate the distribution of the CEE binding-energy parameter lambda for stars with different masses and at different evolutionary stages, and we analyse the effects of envelope mass residual and adiabatic expansion. Due to the envelope mass residual, the lambdas of some donors can increase by one to two orders of magnitude at the late red giant branch and asymptotic giant branch stages. Furthermore, we provide interpolation grids and fitting formulae for these results, which can be readily applied to various binary population synthesis codes.
ER  -