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9 results on '"supernovae and other explosive environments"'

1. Coulomb Dissociation of 27P for Study of 26Si(p,γ)27P Reaction.

Author

Togano, Y., Gomi, T., Motobayashi, T., Ando, Y., Aoi, N., Baba, H., Demichi, K., Elekes, Z., Fukuda, N., Fülöp, Zs., Futakami, U., Hasegawa, H., Higurashi, Y., Ieki, K., Imai, N., Ishihara, M., Ishikawa, K., Iwasa, N., Iwasaki, H., and Kanno, S.

Subjects
*SCISSION (Chemistry), *CHEMICAL reactions, *CHEMICAL kinetics, *PARTICLES (Nuclear physics), *COULOMB functions
Abstract

The Coulomb dissociation of the proton-rich nuclei 27P was studied experimentally using a 27P beam at 57 MeV/nucleon with a lead target. The γ decay widths of the low-lying excited states in 27P were deduced. The resonant capture reaction rate of stellar 26Si(p,γ)27P through these states was estimated using the measured γ decay width. The astrophysical implications derived from the estimated reaction rate is discussed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2006
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2. Gamma-Ray Lines and High-Energy Sources.

Author

Diehl, Roland

Subjects
*GAMMA rays, *NUCLEOSYNTHESIS, *POSITRON annihilation, *ISOTOPES, *INTERSTELLAR medium, *POSITRONS
Abstract

Gamma-ray lines may provide diagnostic information on cosmic high energy sources: They originate from the decay of radioactive nucleosynthesis products, from positron annihilations, and from atomic nuclei which have been excited by energetic collisions. Shortlived isotopes such as 56Ni and 44Ti are produced in supernovae, their gamma-ray line intensities and line profiles reflect kinematics and morphology of the exploding star. Long-lived isotopes such as 26Al, and also the positron annihilation gamma-rays, can be used to study propagation processes in the interstellar medium near high-energy sources, complementing observational time scales at the long end of the range of interest. Such annihilation emission and also lines from excited nuclei near accreting compact stars should reflect energetic conditions at environments which are believed to inject suprathermal particles into relativistic accelerators to produce cosmic rays. New INTEGRAL measurements on these frontiers are discussed in this paper. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2005
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3. Half-lives of rp-process waiting point nuclei.

Author

Sarriguren, P., Álvarez-Rodríguez, R., and de Guerra, E. Moya

Subjects
*NUCLEAR structure, *MICROSCOPY, *NUMERICAL analysis, *PARTICLES (Nuclear physics), *QUASIPARTICLES, *MEAN field theory
Abstract

We give results of microscopic calculations for the half-lives of various proton-rich nuclei in the mass regionA= 60-90, which are involved in the astrophysical rp-process, and which are needed as input parameters of numerical simulations in Nuclear Astrophysics. The microscopic formalism consists of a deformed QRPA approach that involves a self-consistent quasiparticle deformed Skyrme Hartree-Fock basis and residual spin-isospin separable forces in both the particle-hole and particle-particle channels. The strength of the particle-hole residual interaction is chosen to be consistent with the Skyrme effective force and mean-field basis, while that of the particle-particle is globally fixed to ? = 0.07 MeV after a judicious choice from comparison to experimental half-lives. We study and discuss the sensitivity of the half-lives to deformation and residual interactions. [ABSTRACT FROM AUTHOR]

Published
2005
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4. Core-collapse model effects on nucleosynthesis

Author

Fryer, C.L.

Subjects
*SUPERNOVAE, *NUCLEOSYNTHESIS, *GALACTIC X-ray sources, *CATACLYSMIC variable stars, *ELECTRONS, *FORCE & energy
Abstract

Although simulations of the core-collapse supernova mechanism have not yet converged on a final answer, much of the intuition gained from these simulations can change our current picture of supernova nucleosynthesis. Here we review the basic supernova explosion mechanism with an update on the current status of this mechanism. We then discuss, how this picture leads to changes in the current calculations of nucleosynthetic yields from these outbursts. The behavior of the electron fraction, mixing and explosion energy (as a function of mass) are quite different, than the assumptions used in many nucleosynthesis calculations, and we will focus on these issues. [Copyright &y& Elsevier]

Published
2004
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6. Study of the N = 28 shell closure in the Ar isotopic chain

Author

E. Rich, Zsolt Dombrádi, D. Sohler, L. Nalpas, Karl Kratz, Yu. E. Penionzhkevich, J. Gibelin, F. Hammache, S. Franchoo, J.A. Scarpaci, M. Gelin, D. Beaumel, K. W. Kemper, E. C. Pollacco, S. Grévy, S. Fortier, M. Stanoiu, Thomas Rauscher, M. G. St. Laurent, Y. Blumenfeld, F. Nowacki, P. Roussel-Chomaz, O. Sorlin, A. N. Ostrowski, L. Gaudefroy, Erik Tryggestad, S. M. Lukyanov, D. Verney, F. Ibrahim, C. Monrozeau, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), SPIRAL, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Hadron, 21.10.Hw, 21.10.Jx, 25.60.Je, 26.30.+k, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Reaction rate, Spin, Transfer reactions, Atomic orbital, 0103 physical sciences, Nuclear astrophysics, medicine, Astrophysics::Solar and Stellar Astrophysics, Nuclear fusion, Neutron, Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Nucleosynthesis in novae, and isobaric spin, Neutron capture, medicine.anatomical_structure, parity, Physics::Space Physics, Spectroscopic factors, Atomic physics, supernovae and other explosive environments, Nucleus
Abstract

Expérience au GANIL NESTER; The structure of the neutron-rich nucleus $^{47}$Ar has been investigated through the d( $^{46}$Ar, $^{47}$Ar)p transfer reaction. The radioactive beam of $^{46}$Ar at 10A·MeV was provided by the SPIRAL facility at GANIL. The protons corresponding to a neutron pick-up on bound or unbound states mechanism in $^{47}$Ar nuclei were detected at backward angles by the position-sensitive Si array-detector MUST. The transfer-like ejectiles were detected in the SPEG spectrometer. Level scheme, spin assignments and spectroscopic factors have been deduced for $^{47}$Ar and compared to shell model predictions. They suggest a slight erosion of the N = 28 shell gap from the weakening of the spin-orbit interaction arising from the f and p orbitals. These spectroscopic information are subsequently used to infer (n,$\gamma$) reaction rates in the Ar isotopic chain to understand the origin of the $^{48}$Ca/ $^{46}$Ca abnormal isotopic ratio observed in certain inclusions of meteorites.

Published
2006
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7. Photodissociation of p-process nuclei studied by bremsstrahlung-induced activation

Author

K. Kosev, Andreas Wagner, M. Erhard, Ronald Schwengner, Eckart Grosse, N. Nankov, K. D. Schilling, J. Klug, Roland Beyer, Gencho Rusev, Arnd R. Junghans, and C. Nair

Subjects
Physics, Nuclear and High Energy Physics, COSMIC cancer database, Nuclear Theory, Photodissociation, Bremsstrahlung, FOS: Physical sciences, Photonuclear reactions, Nucleosynthesis in novae, p-process, Nuclear physics, Deuterium, Photon absorption and scattering, Nuclide, Irradiation, Nuclear Experiment (nucl-ex), Nuclear Experiment, supernovae and other explosive environments, Radioactive decay
Abstract

A research program has been started to study experimentally the near-threshold photodissociation of nuclides in the chain of cosmic heavy element production with bremsstrahlung from the ELBE accelerator. An important prerequisite for such studies is good knowledge of the bremsstrahlung distribution which was determined by measuring the photodissociation of the deuteron and by comparison with model calculations. First data were obtained for the astrophysically important target nucleus 92-Mo by observing the radioactive decay of the nuclides produced by bremsstrahlung irradiation at end-point energies between 11.8 MeV and 14.0 MeV. The results are compared to recent statistical model calculations., Comment: 6 pages, 8 figures, Proceedings Nuclear Physics in Astrophysics II, May 16-20, 2005, Debrecen, Hungary. The original publication is available at www.eurphysj.org

Published
2006
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8. Photodissociation of p-process nuclei studied by bremsstrahlung induced activation

Author

Erhard, M., Junghans, A. R., Beyer, R., Grosse, E., Klug, J., Kosev, K., Nair, C., Nankov, N., Rusev, G., Schilling, K. D., Schwengner, R., Wagner, A., Erhard, M., Junghans, A. R., Beyer, R., Grosse, E., Klug, J., Kosev, K., Nair, C., Nankov, N., Rusev, G., Schilling, K. D., Schwengner, R., and Wagner, A.

Abstract

A research program has been started to study experimentally the near-threshold photodissociation of nuclides in the chain of cosmic heavy element production with bremsstrahlung from the ELBE accelerator. An important prerequisite for such studies is good knowledge of the bremsstrahlung distribution which was determined by measuring the photodissociation of the deuteron and by comparison with model calculations. First data were obtained for the astrophysically important target nucleus 92-Mo by observing the radioactive decay of the nuclides produced by bremsstrahlung irradiation at end-point energies between 11.8 and 14.0 MeV. The results are compared to recent statistical model calculations.

Published
2006

9. Photodissociation of p-process nuclei studied by bremsstrahlung induced activation

Author

Erhard, M., Junghans, A. R., Beyer, R., Grosse, E., Klug, J., Kosev, K., Nair, C., Nankov, N., Rusev, G., Schilling, K. D., Schwengner, R., Wagner, A., Erhard, M., Junghans, A. R., Beyer, R., Grosse, E., Klug, J., Kosev, K., Nair, C., Nankov, N., Rusev, G., Schilling, K. D., Schwengner, R., and Wagner, A.

Abstract

A research program has been started to study experimentally the near-threshold photodissociation of nuclides in the chain of cosmic heavy element production with bremsstrahlung from the ELBE accelerator. An important prerequisite for such studies is good knowledge of the bremsstrahlung distribution which was determined by measuring the photodissociation of the deuteron and by comparison with model calculations. First data were obtained for the astrophysically important target nucleus 92-Mo by observing the radioactive decay of the nuclides produced by bremsstrahlung irradiation at end-point energies between 11.8 and 14.0 MeV. The results are compared to recent statistical model calculations.

Published
2005

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