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ABSTRACT It has long been speculated that jet feedback from accretion on to the companion during a common envelope (CE) event could affect the orbital evolution and envelope unbinding process. We present global 3D hydrodynamical simulations of CE evolution (CEE) that include a jet subgrid model and compare them with an otherwise identical model without a jet. Our binary consists of a 2-M⊙ red giant branch primary and a 1- or 0.5-M⊙ main sequence (MS) or white dwarf (WD) secondary companion modelled as a point particle. We run the simulations for 10 orbits (40 d). Our jet model adds mass at a constant rate $$\dot{M}_\mathrm{j}$$ of the order of the Eddington rate, with maximum velocity vj of the order of the escape speed, to two spherical sectors with the jet axis perpendicular to the orbital plane. We explore the influence of the jet on orbital evolution, envelope morphology and envelope unbinding, and assess the dependence of the results on the jet mass-loss rate, launch speed, companion mass, opening angle, and accretion rate. In line with our theoretical estimates, jets are choked around the time of first periastron passage and remain choked thereafter. Subsequent to choking, but not before, jets efficiently transfer energy to bound envelope material. This leads to increases in unbound mass of up to $$\sim 10{{\ \rm per\ cent}}$$, as compared to the simulations without jets. We also estimate the cumulative effects of jets over a full CE phase, finding that jets launched by MS and WD companions are unlikely to dominate envelope unbinding.
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Common envelope evolution on the asymptotic giant branch: unbinding within a decade?
ABSTRACT Common envelope (CE) evolution is a critical but still poorly understood progenitor phase of many high-energy astrophysical phenomena. Although 3D global hydrodynamic CE simulations have become more common in recent years, those involving an asymptotic giant branch (AGB) primary are scarce, due to the high computational cost from the larger dynamical range compared to red giant branch (RGB) primaries. But CE evolution with AGB progenitors is desirable to simulate because such events are the likely progenitors of most bi-polar planetary nebulae (PNe), and prominent observational testing grounds for CE physics. Here we present a high-resolution global simulation of CE evolution involving an AGB primary and 1-$$\mathrm{M_\odot }$$ secondary, evolved for 20 orbital revolutions. During the last 16 of these orbits, the envelope unbinds at an almost constant rate of about 0.1–$$0.2\, \mathrm{M_\odot \, yr^{-1}}$$. If this rate were maintained, the envelope would be unbound in less than $$10\, {\rm yr}$$. The dominant source of this unbinding is consistent with inspiral; we assess the influence of the ambient medium to be subdominant. We compare this run with a previous run that used an RGB phase primary evolved from the same 2-$$\mathrm{M_\odot }$$ main-sequence star to assess the influence of the evolutionary state of the primary. When scaled appropriately, the two runs are quite similar, but with some important differences.
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- Award ID(s):
- 1813298
- PAR ID:
- 10163568
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 495
- Issue:
- 4
- ISSN:
- 0035-8711
- Page Range / eLocation ID:
- 4028 to 4039
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/mnras/staa1273
