Simulating the convection in red super-giant stars: wobbling jets in common envelope evolution
Abstract
We use our newly constructed three-dimensional red supergiant (RSG) stellar model, which also mimics nuclear energy production and photospheric emission, to calculate the stochastic component of the angular momentum of the mass that a companion spiraling within the RSG's envelope accretes during common envelope evolution (CEE). The accreted mass has a fixed-direction angular-momentum component arising from the density gradient in the RSG envelope and orbital motion. The angular momentum component with a stochastically varying direction results from vigorous envelope convection. We do not include the companion's influence on the RSG envelope during the CEE and consider an undisturbed, non-rotating RSG stellar model. We find that the fluctuating angular momentum amplitude can be several times the fixed-axis angular momentum. The total specific angular momentum of the accreted mass easily forms intermittent accretion disks around neutron stars and black holes, but it is only marginally sufficient, or not at all, to form accretion disks around main-sequence stellar companions. The intermittent accretion disks we expect to form will launch wobbling jets with varying axes. We discuss aspects of wobbling jets in the CEE and the grazing envelope evolution (GEE), which might precede the CEE or replace it altogether. Studies have claimed that jets are a crucial ingredient in many cases of CEE, and the standard CEE should include jets that the companion launches, before (like the GEE), during, and/or at the exit from the CEE. Our study supports this claim and emphasizes the importance of wobbling jets.
Related
- The Common Envelope Evolution Outcome. III. the Improvement of Stellar Binding Energy with the Envelope Residual
- Common Envelope Evolution: Too stochastic to be deterministic
- Planets surviving common envelope evolution should be rare, massive, and orbit very close to their host star
- Stellar black hole binaries from two common envelope evolution phases in triple stellar systems
- Effect of Neutron Star Jets on Common Envelope Evolution
BibTeX
@misc{hillel2026simulating,
title = {{Simulating the convection in red super-giant stars: wobbling jets in common envelope evolution}},
author = {Shlomi Hillel and Ron Schreier and Noam Soker},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.13023},
eprint = {2607.13023},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.13023},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Simulating the convection in red super-giant stars: wobbling jets in common envelope evolution
AU - Shlomi Hillel
AU - Ron Schreier
AU - Noam Soker
PY - 2026
DA - 2026/09/24
PB - arXiv
DO - 10.48550/arxiv.2607.13023
UR - https://arxiv.org/abs/2607.13023
AB - We use our newly constructed three-dimensional red supergiant (RSG) stellar model, which also mimics nuclear energy production and photospheric emission, to calculate the stochastic component of the angular momentum of the mass that a companion spiraling within the RSG's envelope accretes during common envelope evolution (CEE). The accreted mass has a fixed-direction angular-momentum component arising from the density gradient in the RSG envelope and orbital motion. The angular momentum component with a stochastically varying direction results from vigorous envelope convection. We do not include the companion's influence on the RSG envelope during the CEE and consider an undisturbed, non-rotating RSG stellar model. We find that the fluctuating angular momentum amplitude can be several times the fixed-axis angular momentum. The total specific angular momentum of the accreted mass easily forms intermittent accretion disks around neutron stars and black holes, but it is only marginally sufficient, or not at all, to form accretion disks around main-sequence stellar companions. The intermittent accretion disks we expect to form will launch wobbling jets with varying axes. We discuss aspects of wobbling jets in the CEE and the grazing envelope evolution (GEE), which might precede the CEE or replace it altogether. Studies have claimed that jets are a crucial ingredient in many cases of CEE, and the standard CEE should include jets that the companion launches, before (like the GEE), during, and/or at the exit from the CEE. Our study supports this claim and emphasizes the importance of wobbling jets.
ER -