Three-dimensional simulations of the jet feedback mechanism in common envelope jets supernova

We conduct three-dimensional hydrodynamical simulations of common envelope jets supernova (CEJSN) events where we assume that a neutron star (NS) launches jets as it orbits inside the outer zones of a red supergiant (RSG) envelope, and find the negative jet feedback coefficient to be ~0.1-0.2. This coefficient is the factor by which the jets reduce the mass accretion rate onto the NS as they remove mass from the envelope and inflate bubbles (cocoons). Our results suggest that in most CEJSN events the NS-RSG binary system experiences the grazing envelope evolution (GEE) before it enters a full common envelope evolution (CEE). We also find that the jets induce upward and downward flows in the RSG envelope. These flows together with the strong convection of RSG stars might imply that energy transport by convection in CEJSNe is very important. Because of limited numerical resources we do not include in the simulations the gravity of the NS, nor the accretion process, nor the jets launching process, and nor the gravity of the deformed envelope. Future numerical simulations of CEE with a NS/BH companion should include the accretion process onto the NS (and vary the jets' power accordingly), the full gravitational interaction of the NS with the RSG, and energy transport by the strong convection.Comment: Accepted for publication in MNRA

Stable Fermion Bag Solitons in the Massive Gross-Neveu Model: Inverse Scattering Analysis

Formation of fermion bag solitons is an important paradigm in the theory of hadron structure. We study this phenomenon non-perturbatively in the 1+1 dimensional Massive Gross-Neveu model, in the large $N$ limit. We find, applying inverse scattering techniques, that the extremal static bag configurations are reflectionless, as in the massless Gross-Neveu model. This adds to existing results of variational calculations, which used reflectionless bag profiles as trial configurations. Only reflectionless trial configurations which support a single pair of charge-conjugate bound states of the associated Dirac equation were used in those calculations, whereas the results in the present paper hold for bag configurations which support an arbitrary number of such pairs. We compute the masses of these multi-bound state solitons, and prove that only bag configurations which bear a single pair of bound states are stable. Each one of these configurations gives rise to an O(2N) antisymmetric tensor multiplet of soliton states, as in the massless Gross-Neveu model.Comment: 10 pages, revtex, no figures; v2: typos corrected, references added; v3: version accepted for publication in the PRD. referencess added. Some minor clarifications added at the beginning of section