The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform

D. J. Dean - One of the best experts on this subject based on the ideXlab platform.

  • Nuclear Electron Capture in core collapse supernovae
    Nuclear Physics A, 2005
    Co-Authors: William Raphael Hix, O. B. Messer, Anthony Mezzacappa, J. M. Sampaio, K. Langanke, Gabriel Martínez-pinedo, M. Liebendörfer, D. J. Dean
    Abstract:

    The dynamics of stellar core collapse are strongly dependent on nuclear Electron Capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, Electron Capture on these nuclei has been treated in a highly parameterized fashion, if not ignored. Recent advances in nuclear structure theory have allowed a more realistic treatment to be developed. With this new treatment of Electron Capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the sensitivity of these results to the strength of nuclear Electron Capture.

  • Consequences of nuclear Electron Capture in core collapse supernovae.
    Physical review letters, 2003
    Co-Authors: William Raphael Hix, Anthony Mezzacappa, J. M. Sampaio, K. Langanke, M. Liebendörfer, D. J. Dean, O. E. B. Messer, Gabriel Martínez-pinedo
    Abstract:

    The most important weak nuclear interaction to the dynamics of stellar core collapse is Electron Capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, Electron Capture on these nuclei has been treated in a highly parametrized fashion, if not ignored. With realistic treatment of Electron Capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the ramifications for the postbounce evolution in core collapse supernovae.

  • Competition of Electron Capture and beta-decay rates in supernova collapse
    The Astrophysical Journal Supplement Series, 2000
    Co-Authors: Gabriel Martínez-pinedo, K. Langanke, D. J. Dean
    Abstract:

    We calculate supernova Electron Capture and beta decay rates for various pf-shell nuclei using large-scale shell model techniques. We show that the centroid of the Gamow-Teller strength distribution has been systematically misplaced in previous rate estimates. Our total Electron Capture rates are significantly smaller than currently adopted in core collapse calculations, while the total beta decay rates change less. Our calculation shows that for Electron-to-baryon ratios Ye=0.42-0.46 beta decay rates are larger than the competing Electron Capture rates.

Gabriel Martínez-pinedo - One of the best experts on this subject based on the ideXlab platform.

  • Nuclear Electron Capture in core collapse supernovae
    Nuclear Physics A, 2005
    Co-Authors: William Raphael Hix, O. B. Messer, Anthony Mezzacappa, J. M. Sampaio, K. Langanke, Gabriel Martínez-pinedo, M. Liebendörfer, D. J. Dean
    Abstract:

    The dynamics of stellar core collapse are strongly dependent on nuclear Electron Capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, Electron Capture on these nuclei has been treated in a highly parameterized fashion, if not ignored. Recent advances in nuclear structure theory have allowed a more realistic treatment to be developed. With this new treatment of Electron Capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the sensitivity of these results to the strength of nuclear Electron Capture.

  • Consequences of nuclear Electron Capture in core collapse supernovae.
    Physical review letters, 2003
    Co-Authors: William Raphael Hix, Anthony Mezzacappa, J. M. Sampaio, K. Langanke, M. Liebendörfer, D. J. Dean, O. E. B. Messer, Gabriel Martínez-pinedo
    Abstract:

    The most important weak nuclear interaction to the dynamics of stellar core collapse is Electron Capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, Electron Capture on these nuclei has been treated in a highly parametrized fashion, if not ignored. With realistic treatment of Electron Capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the ramifications for the postbounce evolution in core collapse supernovae.

  • Competition of Electron Capture and beta-decay rates in supernova collapse
    The Astrophysical Journal Supplement Series, 2000
    Co-Authors: Gabriel Martínez-pinedo, K. Langanke, D. J. Dean
    Abstract:

    We calculate supernova Electron Capture and beta decay rates for various pf-shell nuclei using large-scale shell model techniques. We show that the centroid of the Gamow-Teller strength distribution has been systematically misplaced in previous rate estimates. Our total Electron Capture rates are significantly smaller than currently adopted in core collapse calculations, while the total beta decay rates change less. Our calculation shows that for Electron-to-baryon ratios Ye=0.42-0.46 beta decay rates are larger than the competing Electron Capture rates.

K. Langanke - One of the best experts on this subject based on the ideXlab platform.

  • Nuclear Electron Capture in core collapse supernovae
    Nuclear Physics A, 2005
    Co-Authors: William Raphael Hix, O. B. Messer, Anthony Mezzacappa, J. M. Sampaio, K. Langanke, Gabriel Martínez-pinedo, M. Liebendörfer, D. J. Dean
    Abstract:

    The dynamics of stellar core collapse are strongly dependent on nuclear Electron Capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, Electron Capture on these nuclei has been treated in a highly parameterized fashion, if not ignored. Recent advances in nuclear structure theory have allowed a more realistic treatment to be developed. With this new treatment of Electron Capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the sensitivity of these results to the strength of nuclear Electron Capture.

  • Consequences of nuclear Electron Capture in core collapse supernovae.
    Physical review letters, 2003
    Co-Authors: William Raphael Hix, Anthony Mezzacappa, J. M. Sampaio, K. Langanke, M. Liebendörfer, D. J. Dean, O. E. B. Messer, Gabriel Martínez-pinedo
    Abstract:

    The most important weak nuclear interaction to the dynamics of stellar core collapse is Electron Capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, Electron Capture on these nuclei has been treated in a highly parametrized fashion, if not ignored. With realistic treatment of Electron Capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the ramifications for the postbounce evolution in core collapse supernovae.

  • Competition of Electron Capture and beta-decay rates in supernova collapse
    The Astrophysical Journal Supplement Series, 2000
    Co-Authors: Gabriel Martínez-pinedo, K. Langanke, D. J. Dean
    Abstract:

    We calculate supernova Electron Capture and beta decay rates for various pf-shell nuclei using large-scale shell model techniques. We show that the centroid of the Gamow-Teller strength distribution has been systematically misplaced in previous rate estimates. Our total Electron Capture rates are significantly smaller than currently adopted in core collapse calculations, while the total beta decay rates change less. Our calculation shows that for Electron-to-baryon ratios Ye=0.42-0.46 beta decay rates are larger than the competing Electron Capture rates.

William Raphael Hix - One of the best experts on this subject based on the ideXlab platform.

  • Nuclear Electron Capture in core collapse supernovae
    Nuclear Physics A, 2005
    Co-Authors: William Raphael Hix, O. B. Messer, Anthony Mezzacappa, J. M. Sampaio, K. Langanke, Gabriel Martínez-pinedo, M. Liebendörfer, D. J. Dean
    Abstract:

    The dynamics of stellar core collapse are strongly dependent on nuclear Electron Capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, Electron Capture on these nuclei has been treated in a highly parameterized fashion, if not ignored. Recent advances in nuclear structure theory have allowed a more realistic treatment to be developed. With this new treatment of Electron Capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the sensitivity of these results to the strength of nuclear Electron Capture.

  • Consequences of nuclear Electron Capture in core collapse supernovae.
    Physical review letters, 2003
    Co-Authors: William Raphael Hix, Anthony Mezzacappa, J. M. Sampaio, K. Langanke, M. Liebendörfer, D. J. Dean, O. E. B. Messer, Gabriel Martínez-pinedo
    Abstract:

    The most important weak nuclear interaction to the dynamics of stellar core collapse is Electron Capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, Electron Capture on these nuclei has been treated in a highly parametrized fashion, if not ignored. With realistic treatment of Electron Capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the ramifications for the postbounce evolution in core collapse supernovae.

Hideyuki Umeda - One of the best experts on this subject based on the ideXlab platform.

  • evolution of progenitors for Electron Capture supernovae
    The Astrophysical Journal, 2013
    Co-Authors: Koh Takahashi, Takashi Yoshida, Hideyuki Umeda
    Abstract:

    We provide progenitor models for Electron Capture supernovae (ECSNe) with detailed evolutionary calculation. We include minor Electron Capture nuclei using a large nuclear reaction network with updated reaction rates. For Electron Capture, the Coulomb correction of rates is treated and the contribution from neutron-rich isotopes is taken into account in each nuclear statistical equilibrium (NSE) composition. We calculate the evolution of the most massive super asymptotic giant branch stars and show that these stars undergo off-center carbon burning and form ONe cores at the center. These cores become heavier up to the critical mass of 1.367 M{sub Sun} and keep contracting even after the initiation of O+Ne deflagration. Inclusion of minor Electron Capture nuclei causes convective URCA cooling during the contraction phase, but the effect on the progenitor evolution is small. On the other hand, Electron Capture by neutron-rich isotopes in the NSE region has a more significant effect. We discuss the uniqueness of the critical core mass for ECSNe and the effect of wind mass loss on the plausibility of our models for ECSN progenitors.

  • evolution of progenitors for Electron Capture supernovae
    arXiv: Solar and Stellar Astrophysics, 2013
    Co-Authors: Koh Takahashi, Takashi Yoshida, Hideyuki Umeda
    Abstract:

    We provide progenitor models for Electron Capture supernovae (ECSNe) with detailed evolutionary calculation. We include minor Electron Capture nuclei using a large nuclear reaction network with updated reaction rates. For Electron Captures, the Coulomb correction on the rates is treated and contribution of neutron-rich nuclei is taken into account in the nuclear statistical equilibrium (NSE) composition. We calculate the evolution of the most massive super asymptotic giant branch stars and show that these stars undergo off-center carbon burnings and form ONe cores at the center. These cores get heavier up to the critical mass of 1.367 Msun and keep contracting even after the initiation of O+Ne deflagration. Though inclusion of minor Electron Capture nuclei causes convective URCA process at the contraction phase, such process will have minor effect on the evolution. On the other hand, Electron Captures by neutron-rich nuclei in the NSE region have more significant effect. Also, we discuss the uniqueness of the critical core mass for ECSNe and the effect of mass loss on the plausibility of our models for ECSN progenitors.