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Arnould, Michel; Zubini, Fabio

doi:10.1007/978-94-011-8080-1_13

Cited by 10 publications

(15 citation statements)

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“…The C-burning phase raises the very interesting question of the fusion of light heavy ions below the Coulomb barrier, and in particular of the origin of the very pronounced structures observed in the 12 C + 12 C fusion cross section at low energies. The devoted experimental and theoretical works do not provide fully satisfactory solutions ( [23,174,175]).…”

Section: Carbon Burningmentioning

confidence: 99%

Nuclear astrophysics

Arnould¹,

Takahashi²

1999

Rep. Prog. Phys.

167

267

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Nuclear astrophysics is that branch of astrophysics which helps understanding the Universe, or at least some of its many faces, through the knowledge of the microcosm of the atomic nucleus. It attempts to find as many nuclear physics imprints as possible in the macrocosm, and to decipher what those messages are telling us about the varied constituent objects in the Universe at present and in the past. In the last decades much advance has been made in nuclear astrophysics thanks to the sometimes spectacular progress made in the modelling of the structure and evolution of the stars, in the quality and diversity of the astronomical observations, as well as in the experimental and theoretical understanding of the atomic nucleus and of its spontaneous or induced transformations. Developments in other sub-fields of physics and chemistry have also contributed to that advance. Notwithstanding the accomplishment, many longstanding problems remain to be solved, and the theoretical understanding of a large variety of observational facts needs to be put on safer grounds. In addition, new questions are continuously emerging, and new facts endangering old ideas.This review shows that astrophysics has been, and still is, highly demanding to nuclear physics in both its experimental and theoretical components. On top of the fact that large varieties of nuclei have to be dealt with, these nuclei are immersed in highly unusual environments which may have a significant impact on their static properties, the diversity of their transmutation modes, and on the probabilities of these modes. In order to have a chance of solving some of the problems nuclear astrophysics is facing, the astrophysicists and nuclear physicists are obviously bound to put their competence in common, and have sometimes to benefit from the help of other fields of physics, like particle physics, plasma physics or solid-state physics. Given the highly varied and complex aspects, we pick here some specific nuclear physics topics which largely pervade nuclear astrophysics. Direct cross-section measurements 7.3.2. Indirect cross-section measurements 7.4. Neutron capture reactions: Experiments 7.5. Thermonuclear reaction rates: Models 7.5.1. Microscopic models 7.5.2. The potential and DWBA models 7.5.3. Parameter fits 7.5.4. The statistical models 8. Selected topics 8.1. Heavy-element nucleosynthesis by the s-and r-processes of neutron captures 8.1.1. Defining the s-process 8.1.2. Defining the r-process 8.1.3. The s-and r-process contributions to the solar-system composition 8.1.4. Astrophysical sites for the s-and r-processes 8.1.5. Heavy elements in low-metallicity stars 8.2. Cosmochronometry 8.2.1. Nucleo-cosmochronology: generalities 8.2.2. The trans-actinide clocks 8.2.3. The 187 Re -187 Os chronometry 8.3. Type-II supernovae 8.3.1. Evolution of massive stars leading to neutrino-driven supernovae 8.3.2. Nucleosynthesis in the hot bubble: Can the r-process occur ? 8.3.3. Signatures of a large-scale mixing of nucleosynthesis products 9. Summary References * The situ...

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Section: Carbon Burningmentioning

confidence: 99%

Nuclear astrophysics

Arnould¹,

Takahashi²

1999

Rep. Prog. Phys.

167

267

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“…The inverse transformation of 187 Os via free-electron captures is certainly responsible for additional corrections to the stellar 187 Re/ 187 Os abundance ratio (e.g. [5,125]). Further complications arise because these two nuclides can be concomitantly destroyed by neutron captures in certain stellar locations [125].…”

Section: "Long-lived" Nucleo-cosmochronometers: Generalitiesmentioning

confidence: 99%

“…The long-lived 176 Lu (t 1/2 = 41 Gy) has the remarkable property of being shielded from the r-process, and thus to be a pure s-process product. It has been proposed by Dave and his collaborators [19], and independently by [6], to be a potential chronometer for the s-process, the other long-lived radionuclides probing the r-process instead. These early works pointed out some possible uncertainties in the solar 176 Lu abundance, as well as in its production predicted from s-process models.…”

Section: Lu a Long-lived S-process Radionuclidementioning

confidence: 99%

Cosmic radioactivities

Arnould¹,

Prantzos²

1999

New Astronomy

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Radionuclides with half-lives ranging from some years to billions of years presumably synthesized outside of the solar system are now recorded in ``live'' or ``fossil'' form in various types of materials, like meteorites or the galactic cosmic rays. They bring specific astrophysical messages the deciphering of which is briefly reviewed here, with special emphasis on the contribution of Dave Schramm and his collaborators to this exciting field of research. Short-lived radionuclides are also present in the Universe today, as directly testified by the gamma-ray lines emitted by the de-excitation of their daughter products. A short review of recent developments in this field is also presented.Comment: Invited Review to appear in New Astronomy, 16 pages, 2 figure

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“…Reaction rates for medium or heavy nuclei, applied in astrophysical applications, have been calculated until now on the Data tables are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/487/767 basis of the Hauser-Feshbach (HF) statistical model (Hauser & Feshbach 1952), adopting simplified schemes to estimate the capture reaction cross section of a given target nucleus, not only in its ground state but also in the different thermally populated states of the stellar plasma at a given temperature (Arnould 1972;Holmes et al 1976;Woosley et al 1978, Sargood 1982Thielemann et al 1987;Cowan et al 1991;Rauscher & Thielemann 2001;Aikawa et al 2005). Such schemes include a number of approximations that have never been tested, such as the neglect of delayed particle emission during the electromagnetic decay cascade or the absence of the preequilibrium contribution at increasing incident energies or for exotic neutron-rich nuclei.…”

Section: Introductionmentioning

confidence: 99%

Improved predictions of nuclear reaction rates with the TALYS reaction code for astrophysical applications

Goriely¹,

Hilaire

Koning

2008

A&A

242

252

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Context. Nuclear reaction rates of astrophysical applications are traditionally determined on the basis of Hauser-Feshbach reaction codes. These codes adopt a number of approximations that have never been tested, such as a simplified width fluctuation correction, the neglect of delayed or multiple-particle emission during the electromagnetic decay cascade, or the absence of the pre-equilibrium contribution at increasing incident energies. Aims. The reaction code TALYS has been recently updated to estimate the Maxwellian-averaged reaction rates that are of astrophysical relevance. These new developments enable the reaction rates to be calculated with increased accuracy and reliability and the approximations of previous codes to be investigated. Methods. The TALYS predictions for the thermonuclear rates of relevance to astrophysics are detailed and compared with those derived by widely-used codes for the same nuclear ingredients. Results. It is shown that TALYS predictions may differ significantly from those of previous codes, in particular for nuclei for which no or little nuclear data is available. The pre-equilibrium process is shown to influence the astrophysics rates of exotic neutron-rich nuclei significantly. For the first time, the Maxwellian-averaged (n, 2n) reaction rate is calculated for all nuclei and its competition with the radiative capture rate is discussed. Conclusions. The TALYS code provides a new tool to estimate all nuclear reaction rates of relevance to astrophysics with improved accuracy and reliability.

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Cited by 10 publications

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Nuclear astrophysics

Nuclear astrophysics

Cosmic radioactivities

Improved predictions of nuclear reaction rates with the TALYS reaction code for astrophysical applications

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