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How negative feedback and the ambient environment limit the influence of recombination in common envelope evolution.

Authors :
Chamandy, Luke
Carroll-Nellenback, Jonathan
Blackman, Eric G
Frank, Adam
Tu, Yisheng
Liu, Baowei
Zou, Yangyuxin
Nordhaus, Jason
Source :
Monthly Notices of the Royal Astronomical Society. Feb2024, Vol. 528 Issue 1, p234-254. 21p.
Publication Year :
2024

Abstract

We perform 3D hydrodynamical simulations to study recombination and ionization during the common envelope (CE) phase of binary evolution, and develop techniques to track the ionic transitions in time and space. We simulate the interaction of a |$2\, \mathrm{M_\odot }$| red giant branch primary and a |$1\, \mathrm{M_\odot }$| companion modelled as a particle. We compare a run employing a tabulated equation of state (EOS) that accounts for ionization and recombination, with a run employing an ideal gas EOS. During the first half of the simulations, ∼15 per cent more mass is unbound in the tabulated EOS run due to the release of recombination energy, but by simulation end the difference has become negligible. We explain this as being a consequence of (i) the tabulated EOS run experiences a shallower inspiral and hence smaller orbital energy release at late times because recombination energy release expands the envelope and reduces drag, and (ii) collision and mixing between expanding envelope gas, ejecta and circumstellar ambient gas assists in unbinding the envelope, but does so less efficiently in the tabulated EOS run where some of the energy transferred to bound envelope gas is used for ionization. The rate of mass unbinding is approximately constant in the last half of the simulations and the orbital separation steadily decreases at late times. A simple linear extrapolation predicts a CE phase duration of |${\sim}2\, {\rm yr}$|⁠ , after which the envelope would be unbound. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00358711
Volume :
528
Issue :
1
Database :
Academic Search Index
Journal :
Monthly Notices of the Royal Astronomical Society
Publication Type :
Academic Journal
Accession number :
175011126
Full Text :
https://doi.org/10.1093/mnras/stae036