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Titolo: Effect of anisotropic neutrino radiation on supernova explosion energy
Autore: Shimizu, TM; Ebisuzaki, T; Sato, K; Yamada, S;
- Indirizzi:
- RIKEN, Inst Phys & Chem Res, Sci Computat Lab, Wako, Saitama 35101, Japan RIKEN Wako Saitama Japan 35101 i Computat Lab, Wako, Saitama 35101, Japan Univ Tokyo, Sch Sci, Dept Phys, Bunkyo Ku, Tokyo 113, Japan Univ Tokyo Tokyo Japan 113 h Sci, Dept Phys, Bunkyo Ku, Tokyo 113, Japan
- Titolo Testata:
- ASTROPHYSICAL JOURNAL
fascicolo: 2,
volume: 552,
anno: 2001,
parte:, 1
pagine: 756 - 781
- SICI:
- 0004-637X(20010510)552:2<756:EOANRO>2.0.ZU;2-I
- Fonte:
- ISI
- Lingua:
- ENG
- Soggetto:
- CORE COLLAPSE SUPERNOVAE; RIEMANN SOLVER; II SUPERNOVA; SN 1987A; CONVECTION; SIMULATIONS; SPECTROPOLARIMETRY; NUCLEOSYNTHESIS; MECHANISM; ENVELOPE;
- Keywords:
- convection; elementary particles; hydrodynamics; supernova : general;
- Tipo documento:
- Article
- Natura:
- Periodico
- Settore Disciplinare:
- Physical, Chemical & Earth Sciences
- Citazioni:
- 49
- Recensione:
- Indirizzi per estratti:
- Indirizzo: Shimizu, TM RIKEN, Inst Phys & Chem Res, Sci Computat Lab, Wako, Saitama 35101, Japan RIKEN Wako Saitama Japan 35101 ab, Wako, Saitama 35101, Japan
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- Citazione:
- T.M. Shimizu et al., "Effect of anisotropic neutrino radiation on supernova explosion energy", ASTROPHYS J, 552(2), 2001, pp. 756-781
Abstract
Since SN 1987A, many observations have indicated that supernova explosionsare not spherical. The cause of the asymmetric explosion is still controversial (e.g., asymmetry in the envelope, the convective engine in the central core or in the proto-neutron star). In our previous study, anisotropic neutrino radiation has been proposed as an explanation for this asymmetry. Inthis paper we carried out a series of systematic multidimensional numerical simulations in order to investigate the effect of anisotropic neutrino radiation itself on the supernova explosion energy. The neutrino luminosity and the degree of anisotropy in neutrino radiation were assumed as input parameters, and the numerical results for various parameters were compared with each other. It was found that only a few percent of anisotropy in the neutrino emission distribution is sufficient to increase the explosion energy by a large factor. The explosion energy calculated so far in many supernovamodels has tended to be too short to explain the observation. Anisotropy of 10% in neutrino radiation roughly corresponds to an enhancement of 4% in total neutrino luminosity as far as the explosion energy is concerned. The increase in the explosion energy due to anisotropic neutrino radiation can be explained as follows. Anisotropically emitted neutrinos locally heat thesupernova matter and revive a stalled shock wave in the direction of enhanced radiation. The expansion of the gas by the shock propagation results ina decrease in the neutrino cooling (emission) rate that rapidly decreases with the matter temperature. It is this suppression of energy loss that contributes largely to the increase in explosion energy. The efficiency of neutrino heating (absorption) itself is almost unchanged between anisotropic and spherical models with available energy fixed for neutrinos. In order fora stalled shock wave to revive, enhancement of the local intensity in the neutrino flux is of great importance, rather than that of the total neutrino luminosity over all the solid angle. It is first pointed out that such local neutrino heating is capable of triggering a supernova explosion. Anisotropic neutrino radiation is considered to be a plausible mechanism for a "successful" explosion other than the so far suggested "convective trigger."
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/05/13 alle ore 23:48:50