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Titolo: 2DIMENSIONAL HYDRODYNAMICS OF PRECORE COLLAPSE  OXYGEN SHELL BURNING
Autore: BAZAN G; ARNETT D;
 Indirizzi:
 LAWRENCE LIVERMORE NATL LAB,POB 808,L170 LIVERMORE CA 94550 UNIV ARIZONA,STEWARD OBSERV TUCSON AZ 85721
 Titolo Testata:
 The Astrophysical journal
fascicolo: 1,
volume: 496,
anno: 1998,
parte:, 1
pagine: 316  332
 SICI:
 0004637X(1998)496:1<316:2HOPC>2.0.ZU;2H
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 TURBULENT COMPRESSIBLE CONVECTION; PIECEWISEPARABOLIC METHOD; DEEP ATMOSPHERE; POSTEXPLOSION HYDRODYNAMICS; STELLAR INTERIORS; SUPERNOVA EJECTA; II SUPERNOVAE; HELIUM FLASH; NEUTRON STAR; GAMMARAYS;
 Keywords:
 CONVECTION; HYDRODYNAMICS ; NUCLEAR REACTIONS, NUCLEOSYNTHESIS, ABUNDANCES; STARS, INTERIORS; SUPERNOVAE, GENERAL;
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Science Citation Index Expanded
 Citazioni:
 79
 Recensione:
 Indirizzi per estratti:



 Citazione:
 G. Bazan e D. Arnett, "2DIMENSIONAL HYDRODYNAMICS OF PRECORE COLLAPSE  OXYGEN SHELL BURNING", The Astrophysical journal, 496(1), 1998, pp. 316332
Abstract
By direct hydrodynamic simulation, using the piecewise parabolic method code PROMETHEUS, we study the properties of a convective oxygenburning shell in a SN 1987A progenitor star (20 M.) prior to collapse. The convection is too heterogeneous and dynamic to be well approximatedby onedimensional diffusionlike algorithms that have previously been used for this epoch. Qualitatively new phenomena are seen. The simulations are twodimensional, with good resolution in radius and angle, and used a large (90 degrees) slice centered at the equator. The microphysics and the initial model were carefully treated. Many of the qualitative features of previous multidimensional simulations of convection are seen, including large kinetic and acoustic energy fluxes, which are not accounted for by mixing length theory. Small but significant amounts of C12 are mixed nonuniformly into the oxygenburning convection zone, resulting in hot spots of nuclear energy production that are more than an order of magnitude more energetic than the oxygen flame itself, Density perturbations (up to 8%) occur at the ''edges'' of the convective zone and are the result of gravity waves generated by interaction of penetrating flows into the stable region. Perturbations of temperature and Ye(or neutron excess eta) at the base of the convective zone are of sufficient magnitude to create angular inhomogeneities in explosive nucleosynthesis products and need to be included in quantitative estimates of yields. Combined with the plumelike velocity structure arising from convection, the perturbations will contribute to themixing of Ni56 throughout supernovae envelopes. Runs of different resolution and angular extent were performed to test the robustness of these simulations.
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Documento generato il 27/11/20 alle ore 16:07:03