skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: From multifragmentation to supernovae and neutron stars

Abstract

The thermodynamics properties of globally neutral dense stellar matter are analyzed both in terms of mean field instabilities and structures beyond the mean field. The mean field response to finite wavelength fluctuations is calculated with the realistic Sly230a effective interaction. A Monte Carlo simulation of a schematic lattice Hamiltonian shows the importance of calculations beyond the mean field to calculate the phase diagram of stellar matter. The analogies and differences respect to the thermodynamics of nuclear matter and finite nuclei are stressed.

Authors:
; ;  [1];  [2];  [1];  [3]
  1. GANIL (DSM - CEA / IN2P3 - CNRS), B.P.5027, F-14076 Caen Cedex 5 (France)
  2. LPC Caen - IN2P3 - CNRS/EnsiCaen et Universite, F-14050 Caen Cedex (France)
  3. (France)
Publication Date:
OSTI Identifier:
21054835
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 884; Journal Issue: 1; Conference: 6. Latin American symposium on nuclear physics and applications, Iguazu (Argentina), 3-7 Oct 2005; Other Information: DOI: 10.1063/1.2710599; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPUTERIZED SIMULATION; FLUCTUATIONS; HAMILTONIANS; INSTABILITY; MEAN-FIELD THEORY; MONTE CARLO METHOD; NEUTRON STARS; NUCLEAR FRAGMENTATION; NUCLEAR MATTER; PHASE DIAGRAMS; S CODES; THERMODYNAMICS

Citation Formats

Chomaz, Ph., Napolitani, P., Hasnaoui, K., Gulminelli, F., Ducoin, C., and LPC Caen - IN2P3 - CNRS / EnsiCaen et Universite, F-14050 Caen Cedex. From multifragmentation to supernovae and neutron stars. United States: N. p., 2007. Web. doi:10.1063/1.2710599.
Chomaz, Ph., Napolitani, P., Hasnaoui, K., Gulminelli, F., Ducoin, C., & LPC Caen - IN2P3 - CNRS / EnsiCaen et Universite, F-14050 Caen Cedex. From multifragmentation to supernovae and neutron stars. United States. doi:10.1063/1.2710599.
Chomaz, Ph., Napolitani, P., Hasnaoui, K., Gulminelli, F., Ducoin, C., and LPC Caen - IN2P3 - CNRS / EnsiCaen et Universite, F-14050 Caen Cedex. Mon . "From multifragmentation to supernovae and neutron stars". United States. doi:10.1063/1.2710599.
@article{osti_21054835,
title = {From multifragmentation to supernovae and neutron stars},
author = {Chomaz, Ph. and Napolitani, P. and Hasnaoui, K. and Gulminelli, F. and Ducoin, C. and LPC Caen - IN2P3 - CNRS / EnsiCaen et Universite, F-14050 Caen Cedex},
abstractNote = {The thermodynamics properties of globally neutral dense stellar matter are analyzed both in terms of mean field instabilities and structures beyond the mean field. The mean field response to finite wavelength fluctuations is calculated with the realistic Sly230a effective interaction. A Monte Carlo simulation of a schematic lattice Hamiltonian shows the importance of calculations beyond the mean field to calculate the phase diagram of stellar matter. The analogies and differences respect to the thermodynamics of nuclear matter and finite nuclei are stressed.},
doi = {10.1063/1.2710599},
journal = {AIP Conference Proceedings},
number = 1,
volume = 884,
place = {United States},
year = {Mon Feb 12 00:00:00 EST 2007},
month = {Mon Feb 12 00:00:00 EST 2007}
}
  • We examine the feasibility of oscillations of Dirac and Majorana neutrinos in a strong magnetic field (assuming a nonvanishing neutrino magnetic moment). We determine the critical magnetic field B{sub cr}({Delta}m{sub v}{sup 2}, 0, n{sub eff}, E{sub v}0(t)) as a function of the neutrino mass difference, the vacuum mixing angle, the effective mass density, the neutrino energy, and the angle specifying the variation of the magnetic field in the plane transverse to the neutrino`s motion. The condition under which magnetic field-induced neutrino oscillations are significant are discussed. We study the possibility that such oscillations come about in supernova explosions, neutron stars,more » the sun, and the interstellar medium. We analyze the possible conversion of half the active neutrinos in a beam into sterile neutrinos when the beam emerges form the surface of a neutron star (cross-boundary effect), as well as when it crosses the interface between internal layers of a neutron star. 41 refs.« less
  • The final stage of stellar evolution is studied from a theoretical point of view. Two types of stellar instabilities (hydrostatic and dynamical) are studied. It is concluded that at a temperature of T approximates 6 x 10/sup 9/ deg K, both hydrostatic instability, which is induced by the photodisintegration of iron into helium (phase change), and dynamical instability, which is induced by the annihilation process of neutrino production, can cause a star to collapse to beyond recovery. Neutrino processes involving electron-neutrinos and mu - neutrinos prohibit any temperature rise in the star during the collapse phase. Hence the collapse willmore » take place under zero temperature conditions (kT << Fermi energy of electrons). The structure of static, zero temperature stars is reviewed. When the density is less than 10/sup 8/ gm/cm/sup 3/ the star is composed of ordinary ionized nuclei. When the mass approaches 1.4 M/sub sub solar / the density reaches a value that the electron zero point energy (Fermi energy) exceeds the energy difference between isobars. Inverse beta reactions then take place, decreasing the number of electrons, causing instability (hydrostatic). Because of this instability, no star exists whose density ranges from 10/sup 9/ to 10/sup 13/ gm/cm/sup 3/. After a density of 10/sup 13/ gm/cm/ sup 3/ is reached, inverse beta reactions have eliminated all but a very small number of electrons. No nuclei can exist and the star is predominantiy made of neutrons. Such a high concentration of mass produces a large curvature of space- time near the star. General relativity theory is used to describe the structure of such stars. General relativity theory predicts the existence of singularities. Two kinds of gravitational singularities may exist, according to a static, general relativistic description of cold stars. One kind of singularity corresponds to a classical situation that, at the center of such a star the gravitational potential of a test body is equal to its rest energy. Hence matter disappears'' through this kind of singularity. The other singularity corresponds to the same situation except the whole star cuts itself off'' from the rest of the universe by producing a large curvature near the stir such that not even photons may leave it. It is indicated by work done in the past that a static description is probably unrealistic. Even in a gedanken sense, slowly adding material to a star will inevitably cause it to collapse dynimicilly. No completely satisfactory solution for a dynamically collapsing star has been found. The fate of collapsing massive stars (which are believed to be related to supernovas that occur at a rite of around one per hundred years per galaxy) is hence unknown, even in a theoretical sense. The surface of the remains of such stars, if visible at all, will have a temperature of around 10/sup 6/ to 10/sup 7 deg K. Most of the radiation from such stars will lie in the x-ray band ind will not penetrate through our atmosphere. Hence, for the detection of such stars an orbiting telescope working in the near x-ray band will be most useful. (auth)« less