SELF-SUSTAINED ASYMMETRY OF LEPTON-NUMBER EMISSION: A NEW PHENOMENON DURING THE SUPERNOVA SHOCK-ACCRETION PHASE IN THREE DIMENSIONS

被引：144

作者：

Tamborra, Irene ^{[1
]}

Hanke, Florian ^{[2
,3
]}

Janka, Hans-Thomas ^{[2
]}

Mueller, Bernhard ^{[2
]}

Raffelt, Georg G. ^{[1
]}

Marek, Andreas ^{[4
]}

机构：

[1] Max Planck Inst Phys & Astrophys, Werner Heisenberg Inst, D-80805 Munich, Germany

[2] Max Planck Inst Astrophys, D-85748 Garching, Germany

[3] Tech Univ Munich, Dept Phys, D-85748 Garching, Germany

[4] Rechenzentrum Max Planck Gesell, D-85741 Garching, Germany

来源：

ASTROPHYSICAL JOURNAL | 2014年 / 792卷 / 02期

基金：

美国国家科学基金会;

关键词：

hydrodynamics; instabilities; neutrinos; supernovae: general; CORE-COLLAPSE SUPERNOVAE; NEUTRON-STAR KICKS; GRAVITATIONAL-WAVE SIGNALS; ADVECTIVE-ACOUSTIC CYCLE; EQUATION-OF-STATE; 3-DIMENSIONAL SIMULATIONS; DRIVEN CONVECTION; MASSIVE STARS; HYDRODYNAMICS SIMULATIONS; SPECTRA FORMATION;

D O I：

10.1088/0004-637X/792/2/96

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

During the stalled-shock phase of our three-dimensional, hydrodynamical core-collapse simulations with energy-dependent, three-flavor neutrino transport, the lepton-number flux (nu(e) minus (nu) over bar (e)) emerges predominantly in one hemisphere. This novel, spherical-symmetry breaking neutrino-hydrodynamical instability is termed LESA for "Lepton-number Emission Self-sustained Asymmetry." While the individual nu(e) and (nu) over bar (e) fluxes show a pronounced dipole pattern, the heavy-flavor neutrino fluxes and the overall luminosity are almost spherically symmetric. Initially, LESA seems to develop stochastically from convective fluctuations. It exists for hundreds of milliseconds or more and persists during violent shock sloshing associated with the standing accretion shock instability. The nu(e) minus (nu) over bar (e) flux asymmetry originates predominantly below the neutrinosphere in a region of pronounced proto-neutron star (PNS) convection, which is stronger in the hemisphere of enhanced lepton-number flux. On this side of the PNS, the mass accretion rate of lepton-rich matter is larger, amplifying the lepton-emission asymmetry, because the spherical stellar infall deflects on a dipolar deformation of the stalled shock. The increased shock radius in the hemisphere of less mass accretion and minimal lepton-number flux ((nu) over bar (e) flux maximum) is sustained by stronger convection on this side, which is boosted by stronger neutrino heating due to <is an element of((nu) over bare)> > <is an element of(nu e)> Asymmetric heating thus supports the global deformation despite extremely nonstationary convective overturn behind the shock. While these different elements of the LESA phenomenon form a consistent picture, a full understanding remains elusive at present. There may be important implications for neutrino-flavor oscillations, the neutron-to-proton ratio in the neutrino-heated supernova ejecta, and neutron-star kicks, which remain to be explored.

引用

页数：20