view Abstract Citations (1442) References (91) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Accreting white dwarf models for type I supern. III. Carbon deflagration supernovae. Nomoto, K. ; Thielemann, F. -K. Yokoi, The carbon in accreting C + O dwarfs are presented as a plausible model Type evolution of the is calculated from beginning accretion. relatively rapid accretion studied here (Mdot > 4 x 10-8 Msun yr-1) leads to initiation at center. Subsequent...

The major uncertainties involved in the Chandrasekhar mass models for Type Ia supernovae (SNe Ia) are related to companion star of their accreting white dwarf progenitor (which determines accretion rate and consequently carbon ignition density) flame speed after ignition. We calculate explosive nucleosynthesis relatively slow deflagrations with a variety deflagration speeds densities put new constraints on above key quantities. abundance Fe group, particular neutron-rich species like...

We present results from the JINA REACLIB project, an ongoing effort to maintain a current and accurate library of thermonuclear reaction rates for astrophysical applications. Ongoing updates are transparently documented version tracked, any set is publicly available can be downloaded via Web interface at http://groups.nscl.msu.edu/jina/reaclib/db/. discuss here our V1.0, snapshot recommended stable explosive hydrogen helium burning. show that updated lead modest but significant changes in...

The production site of the neutron-rich heavy elements that are formed by rapid neutron capture (the r-process) is still unknown despite intensive research. Here we show detailed studies a scenario has been proposed earlier Lattimer & Schramm, Symbalisty Eichler et al., and Davies namely merger two stars. results hydrodynamic full network calculations combined in order to investigate relevance this for r-process nucleosynthesis. Sufficient material ejected explain amount nuclei Galaxy...

view Abstract Citations (697) References (136) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Core-Collapse Supernovae and Their Ejecta Thielemann, Friedrich-Karl ; Nomoto, Ken'ichi Hashimoto, Masa-Aki We present the detailed isotopic composition for 13, 15, 20, 25 Msun stars, based on induced super- nova calculations, which lead to explosive Si, 0, Ne, C burning during supernova outburst. The calculations made use of inferred mass cuts between central...

We present nuclear reaction network calculations to investigate the influence of structure on rp-process between Ge and Sn in various scenarios. Due lack experimental data for neutron-deficient nuclei this region, we discuss currently available model predictions masses deformations as well methods calculating rates (Hauser-Feshbach) β-decay (QRPA shell model). In addition, apply a valence nucleon (NpNn) correlation scheme prediction deformations. also describe 2p-capture reactions, which had...

We present a new nucleosynthesis process that we denote as the nu p process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this antineutrino absorptions environment produce neutrons are immediately captured by neutron-deficient nuclei. This allows for of nuclei with mass numbers A>64, , making possible candidate to explain origin solar abundances (92,94)Mo and (96,98)Ru. also offers natural explanation large abundance Sr...

We calculate the rapid proton ( rp) capture process of hydrogen burning on surface an accreting neutron star with updated reaction network that extends up to Xe, far beyond previous work. In both steady-state nuclear appropriate for rapidly stars (such as magnetic polar caps x-ray pulsars) and unstable type I bursts, we find rp ends in a closed SnSbTe cycle. This prevents synthesis elements heavier than Te has important consequences burst profiles, composition stars, potentially galactic...

The production of about half the heavy elements found in nature is assigned to a specific astrophysical nucleosynthesis process: rapid neutron capture process (r-process). Although this idea has been postulated more than six decades ago, full understanding faces two types uncertainties/open questions: (a) path nuclear chart runs close neutron-drip line, where presently only limited experimental information available, and one rely strongly on theoretical predictions for properties. (b) While...

We examine magnetorotationally driven supernovae as sources of r-process elements in the early Galaxy. On basis thermodynamic histories tracer particles from a three-dimensional magnetohydrodynamical core-collapse supernova model with approximated neutrino transport, we perform nucleosynthesis calculations and without considering effects absorption reactions on electron fraction (Ye) during post-processing. find that peak distribution Ye ejecta is shifted ∼0.15 to ∼0.17 broadened toward...

Massive stars end their life in an explosion event with kinetic energies of the order 1 Bethe. Immediately after has been launched, a region low density and high entropy forms behind ejecta which is continuously subject to neutrino heating. The neutrinos emitted from remnant at center, protoneutron star (PNS), heat material above PNS surface. This partly converted into energy accelerates outflow that known as driven wind. For first time, we simulate collapse, bounce, wind phases consistently...

We follow the longterm evolution of dynamic ejecta neutron star mergers for up to 100 years and over a density range roughly 40 orders magnitude. include nuclear energy input from freshly synthesized, radioactively decaying nuclei in our simulations study its effects on remnant dynamics. Although heating substantially alters evolution, we find that running networks purely hydrodynamic (i.e. without heating) yields actually acceptable nucleosynthesis results. The main effect radioactive is...

Neutrino-driven winds, which follow core-collapse supernova explosions, present a fascinating nuclear astrophysics problem that requires understanding advanced simulations, the properties of matter and neutrino interactions under extreme conditions, structure reactions exotic nuclei, comparisons against forefront astronomical observations. The neutrino-driven wind has attracted vast attention over last 20 years as it was suggested to be candidate for site where half heavy elements are...

Rotation was shown to have a strong impact on the structure and light element nucleosynthesis in massive stars. In particular, models including rotation can reproduce primary nitrogen observed halo extremely metal-poor (EMP) Additional exploratory showed that may enhance $s$-process production at low metallicity. Here we present large grid of star full network study weak $s$-process. We explore possibility producing significant amounts elements beyond strontium peak, which is where usually...

The predicted nucleosynthesis products of Type Ia and II supernovae are combined with various parameter ratios compared the solar abundances heavy elements their isotopes, also in LMC SMC. Aided by a reasonable model galactic chemical evolution, ratio total numbers (of all time) to that best reproduces observed is determined be NIa/NII = 0.15 for Galaxy, agreement current observations. For MCs, however, this larger than yielding 0.2–0.3. We discuss several possible star formation history...

view Abstract Citations (335) References (67) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Isotopic r-Process Abundances and Nuclear Structure Far from Stability: Implications for the Mechanism Kratz, Karl-Ludwig ; Bitouzet, Jean-Philippe Thielemann, Friedrich-Karl Moeller, Peter Pfeiffer, Bernd The study employs full isotopic r-process abundances in nature a unified model all nuclear properties involved to uniquely deduce conditions necessary produce such...

The influence of the initial composition exploding white dwarf on nucleosynthesis, light curves and spectra Type Ia supernovae has been studied in order to evaluate size evolutionary effects cosmological time scales, how can be recognized one may able correct for them. calculations are based a set delayed detonation models which give good account optical infrared spectral evolution. explosions calculated using one- dimensional Lagrangian radiation-hydro code including nuclear network. NLTE-...

The prediction of cross sections for nuclei far off stability is crucial in the field nuclear astrophysics. In recent calculations level density---as an important ingredient to statistical model (Hauser-Feshbach)---has shown highest uncertainties. We present a global parametrization densities within back-shifted Fermi-gas formalism. Employment energy-dependent density parameter $a$, based on microscopic corrections from finite range droplet mass formula, and backshift $\ensuremath{\delta}$,...

The astrophysical nature of r-process sites is a long-standing mystery and many probable sources have been suggested, among them lower-mass core-collapse supernovae (in the range 8–), higher-mass (with masses 20 ) neutron star mergers. In this work, we present detailed inhomogeneous chemical evolution study that considers for first time mergers as major sources, compare scenario to ones in which act dominant sites. We conclude that, due lack reliable iron yields function progenitor mass, it...

We report on the stellar core collapse, bounce, and postbounce evolution of a $13 {\mathrm{M}}_{\ensuremath{\bigodot}}$ star in self-consistent general relativistic spherically symmetric simulation based Boltzmann neutrino transport. conclude that approximations to exact transport omission effects were not alone responsible for failure numerous preceding attempts model supernova explosions spherical symmetry. Compared simulations Newtonian gravity, results smaller shock radius. however argue...

We present an implicit finite difference representation for general relativistic radiation hydrodynamics in spherical symmetry. Our code, Agile-Boltztran, solves the Boltzmann transport equation angular and spectral neutrino distribution functions self-consistent simulations of stellar core collapse postbounce evolution. It implements a dynamically adaptive grid comoving coordinates. Most macroscopically interesting physical quantities are defined by expectation values function. optimize...