Nucleosynthesis

Truran, J. W.

doi:10.1146/annurev.ns.34.120184.000413

Cited by 47 publications

(14 citation statements)

References 158 publications

(217 reference statements)

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“…It was found that only data from c o l m n 5 are in agreement with column 2, except for 7Li. Most 7Li was formed in the Big Bang and some other sources (Truran, 1984;Boesgaard, 1985;Arnould, 1986;Reeves, 1994). Thus, the B solar-system abundance and the lightelement ratio can be best explained by the bombardment of interstellar medium by galactic cosmic rays, whose energy spectrum is a combination of the detected spectrum and a very intense lowenergy component in the form of E-' .…”

Section: Solar-system Abundances?mentioning

confidence: 99%

Boron cosmochemistry. Part II: Boron nucleosynthesis and condensation temperature

Zhai

1995

Meteoritics

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The new B solar-system abundance calculated by Zhai and Shaw (1994), 16.9 atoms/106 Si (or 606 atoms/10'2 H) is used to reevaluate the different possibilities of LiBeB (except 'Li) nucleosynthesis. The revised abundances support two models: (1) Light elements were formed by continual bombardment of interstellar medium (ISM) by galactic cosmic rays (GCRs), but these galactic cosmic rays should contain a very intense low-energy component, in the form of E-' , which cannot be observed near the Earth due to solar modulation effects; (2) Light elements are a mixture of two sources. In the first source, light elements were synthesized by continual bombardment of interstellar medium by galactic cosmic rays. In the second source, they were made by the interactions of C and 0 nuclei ejected from supernovae with the H and He in the surrounding gas. The first source constitutes -46% of total B.The Si-normalized and CI-meteorite-normalized abundances of common and volatile elements in carbonaceous chondrites show a linear correlation with their condensation temperatures. Using this relationship and the normalized B abundances in CM, CO, and CV meteorites, we can estimate the B condensation temperature to be -910 K, which is similar to Ga. Author Observed solar-system abundance* Conclusion for LiBeB Major source Li Be B Nucleosynthesis Meneguzzi eta[. (1971) Weller et al. (1977) Walker et al. (1985) Present work Solar photosphere CI meteorites Stellar photosphere CI meteorites lo** 53,197-214. COMPTEL observations of the orion complex: Evidence for cosmic-ray induced gamma-ray lines. Astron. Astrophys. 281, L5-L8. BOESGAARD A. M. (1985) Big Bang nucleosynthesis: Theories and observations. Ann. Rev. Astrophys. 23,319-378.BOESGAARD A. M. AND HEACOX W. D. (1978) The abundance of boron in Band A-type stars. Astrophys. J. 226,

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Section: Solar-system Abundances?mentioning

confidence: 99%

Boron cosmochemistry. Part II: Boron nucleosynthesis and condensation temperature

Zhai

1995

Meteoritics

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“…This means translated into concentrations C, of the cosmogenic nuclide i --= p¡-Aphys · Ci+2 ~ • c¡ ~ Σλ" · c¡. d/ j Mj j (8) The sources of all the cosmogenic nuclides in question are mainly in the troposphere. Given the largest halflive of these cosmogenic nuclides being 15.7 Ma there are definite sinks in which they can finally decay, i.e.…”

Section: Large-scale Environmental Processesmentioning

confidence: 99%

Long-Lived Radionuclides as Tracers in Terrestrial and Extraterrestrial Matter

Michel

1999

Radiochimica Acta

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Environmental radioactivity / Cosmogenic radionuclides / Long-lived radionuclides / Accelerator mass spectrometry / Natural and mass-made tracers SummaryRadionuclides in nature offer unique opportunities for radioactive dating and tracing of natural and man-made processes. Naturally occurring radionuclides with half-lives between a few days and IO 12 a have found widespread applications some of which are surveyed here. After a short glance on radionuclide production in stellar nucleosynthesis and on extinct radionuclides in the early solar system, applications are discussed of the long-lived (5 ka < T 1/2 < 16 Ma) radionuclides 10 Be, 14 C, 26 Al, ,6 C1, 41 Ca, "Mn, 59 Ni, and 129 I in cosmochemistry and -physics and in the earth and environmental sciences. These nuclides occur in nature as cosmogenic and partially as radiogenic nuclides and some of them were brought into the terrestrial environment by man. Methods to analyze them at their natural levels are reviewed. Applications are highlighted which cover the cosmic ray record in extraterrestrial matter and in various terrestrial compartments and archives. Emphasis is put on the distinction of mechanisms affecting constancy or variability of the observed natural radionuclide abundances. Finally, the longterm human impact on the radiation environment and the relevance of long-lived radionuclides for the human radiation exposure is discussed. Radionuclides in natureRadioactive nuclides with half-lives between 7.2 · IO 24 a ( I28 Te) and 17 ns ( 212m Po) occur naturally in the solar system and in our terrestrial environment as primordial, radiogenic, nucleogenic or cosmogenic nuclides. More than 20 primordial radionuclides, among them <°K, 87 Rb, 232 Th, 235 U, and 238 U, have sufficiently long half-lives to survive the time since the closing of the solar system. Radionuclides with shorter half-lives are continuously produced. Radiogenic nuclides originate from radioactive decay or spontaneous fission of primordial radionuclides. Nucleogenic ones are produced by nuclear reactions induced by α-particles and neutrons from radioactive decay and spontaneous fission, respectively. Finally, cosmogenic nuclides are the products of interactions of primary and secondary solar and galactic cosmic ray particles with matter. *

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“…Extensive calculations of explosive carbon, neon, oxygen, and silicon burning, appropriate for supernova explosions, have already been performed in the late 60s and early 70s with the accuracies possible in those days and detailed discussions about the expected abundance patterns (for a general review see Trimble 1975;Truran 1985). More recent overviews in the context of stellar models are given by Trimble (1991) and Arnett (1995).…”

Section: Explosive Burningmentioning

confidence: 99%

Nucleosynthesis basics and applications to supernovae

Thielemann¹,

Rauscher²,

Freiburghaus³

et al. 1998

Nuclear and Particle Astrophysics

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This review concentrates on nucleosynthesis processes in general and their applications to massive stars and supernovae. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates and nuclear reaction networks. The required nuclear physics input for reaction rates is discussed, i.e. cross sections for nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and beta-decay half-lives. We examine especially the present state of uncertainties in predicting thermonuclear reaction rates, while the status of experiments is discussed by others in this volume (see M. Wiescher). It follows a brief review of hydrostatic burning stages in stellar evolution before discussing the fate of massive stars, i.e. the nucleosynthesis in type II supernova explosions (SNe II). Except for SNe Ia, which are explained by exploding white dwarfs in binary stellar systems (which will not be discussed here), all other supernova types seem to be linked to the gravitational collapse of massive stars (M>8M ) at the end of their hydrostatic evolution. SN1987A, the first type II supernova for which the progenitor star was known, is used as an example for nucleosynthesis calculations. Finally, we discuss the production of heavy elements in the r-process up to Th and U and its possible connection to supernovae.

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Nucleosynthesis

Cited by 47 publications

References 158 publications

Boron cosmochemistry. Part II: Boron nucleosynthesis and condensation temperature

Boron cosmochemistry. Part II: Boron nucleosynthesis and condensation temperature

Long-Lived Radionuclides as Tracers in Terrestrial and Extraterrestrial Matter

Nucleosynthesis basics and applications to supernovae

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