2001ApJ...554..578W -
Astrophys. J., 554, 578-586 (2001/June-2)
The r-process in neutrino-driven winds from nascent, ``Compact'' neutron stars of core-collapse supernovae.
WANAJO S., KAJINO T., MATHEWS G.J. and OTSUKI K.
Abstract (from CDS):
We present calculations of r-process nucleosynthesis in neutrino-driven winds from the nascent neutron stars of core-collapse supernovae. A full dynamical reaction network for both the α-rich freezeout and the subsequent r-process is employed. The physical properties of the neutrino-heated ejecta are deduced from a general relativistic model in which spherical symmetry and steady flow are assumed. Our results suggest that proto-neutron stars with a large compaction ratio provide the most robust physical conditions for the r-process. The third peak of the r-process is well reproduced in the winds from these ``compact'' proto-neutron stars even for a moderate entropy, ∼100NAk-200NAk, and a neutrino luminosity as high as ∼1052 ergs.s–1. This is due to the short dynamical timescale of material in the wind. As a result, the overproduction of nuclei with A≲120 is diminished (although some overproduction of nuclei with A~90 is still evident). The abundances of the r-process elements per event is significantly higher than in previous studies. The total integrated nucleosynthesis yields are in good agreement with the solar r-process abundance pattern. Our results have confirmed that the neutrino-driven wind scenario is still a promising site in which to form the solar r-process abundances. However, our best results seem to imply both a rather soft neutron-star equation of state and a massive proto-neutron star that is difficult to achieve with standard core-collapse models. We propose that the most favorable conditions perhaps require that a massive supernova progenitor forms a massive proto-neutron star by accretion after a failed initial neutrino burst.
Abstract Copyright:
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Journal keyword(s):
Nuclear Reactions, Nucleosynthesis, Abundances - Stars: Abundances - Stars: Mass Loss - Stars: Neutron - Stars: Supernovae: General
Simbad objects:
2
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