Effect of Neutron Star Jets on Common Envelope Evolution
Abstract
The common envelope (CE) phase is a key stage in binary star evolution that is still not very well understood. Once engulfed by the giant star, the binary companion may accrete envelope material. For neutron star (NS) companions, such accretion may in principle occur at mass rates several orders of magnitude above the Eddington limit and may result in outflows dominated by powerful bi-polar jets with mass-loss rates similar to the accretion rates. Such jets would impact the morphology of the system and the rate of envelope unbinding, which affect the duration and outcome of the CE event. Employing 3D global hydrodynamic simulations, we study the role of such NS jets in a CE event involving a red giant branch star. The jets eventually drill through and break out of the envelope, producing prominent low-density bi-polar lobes. The jets cause about twice as much envelope mass to be unbound (∼20% of the envelope) as compared to simulations of the same duration without NS jets (∼10%). However, the rate of mass unbinding due to the jets decreases towards the ends of the simulations as the jets break out and energetically decouple from the envelope. Moreover, jet activity leads to slightly reduced drag on the binary, decreasing the rate of orbital energy transfer to the envelope. Hence, while such powerful jets can play an important role, negative feedback effects tend to prevent them from dominating envelope unbinding and dictating CE outcomes.
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BibTeX
@misc{gurjar2026effect,
title = {{Effect of Neutron Star Jets on Common Envelope Evolution}},
author = {Deepanshu Gurjar and Luke Chamandy and Eric G. Blackman and Yangyuxin Zou and Baowei Liu and Jason Nordhaus},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.10267},
eprint = {2607.10267},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.10267},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Effect of Neutron Star Jets on Common Envelope Evolution
AU - Deepanshu Gurjar
AU - Luke Chamandy
AU - Eric G. Blackman
AU - Yangyuxin Zou
AU - Baowei Liu
AU - Jason Nordhaus
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2607.10267
UR - https://arxiv.org/abs/2607.10267
AB - The common envelope (CE) phase is a key stage in binary star evolution that is still not very well understood. Once engulfed by the giant star, the binary companion may accrete envelope material. For neutron star (NS) companions, such accretion may in principle occur at mass rates several orders of magnitude above the Eddington limit and may result in outflows dominated by powerful bi-polar jets with mass-loss rates similar to the accretion rates. Such jets would impact the morphology of the system and the rate of envelope unbinding, which affect the duration and outcome of the CE event. Employing 3D global hydrodynamic simulations, we study the role of such NS jets in a CE event involving a red giant branch star. The jets eventually drill through and break out of the envelope, producing prominent low-density bi-polar lobes. The jets cause about twice as much envelope mass to be unbound (∼20% of the envelope) as compared to simulations of the same duration without NS jets (∼10%). However, the rate of mass unbinding due to the jets decreases towards the ends of the simulations as the jets break out and energetically decouple from the envelope. Moreover, jet activity leads to slightly reduced drag on the binary, decreasing the rate of orbital energy transfer to the envelope. Hence, while such powerful jets can play an important role, negative feedback effects tend to prevent them from dominating envelope unbinding and dictating CE outcomes.
ER -