452 research outputs found
Dynamics of solar wind protons reflected by the Moon
Solar system bodies that lack a significant atmosphere and significant
internal magnetic fields, such as the Moon and asteroids, have been considered
as passive absorbers of the solar wind. However, ion observations near the Moon
by the SELENE spacecraft show that a fraction of the impacting solar wind
protons are reflected by the surface of the Moon. Using new observations of the
velocity spectrum of these reflected protons by the SARA experiment on-board
the Chandrayaan-1 spacecraft at the Moon, we show by modeling that the
reflection of solar wind protons will affect the global plasma environment.
These global perturbations of the ion fluxes and the magnetic fields will
depend on microscopic properties of the object's reflecting surface. This solar
wind reflection process could explain past ion observations at the Moon, and
the process should occur universally at all atmosphereless non-magnetized
objects.Comment: 12 pages, 8 figure
The extended, relativistic hyperon star model
In this paper an equation of state of neutron star matter which includes
strange baryons in the framework of Zimanyi and Moszkowski (ZM) model has been
obtained. We concentrate on the effects of the isospin dependence of the
equation of state constructing for the appropriate choices of parameters the
hyperons star model. Numerous neutron star models show that the appearance of
hyperons is connected with the increasing density in neutron star interiors.
Various studies have indicated that the inclusion of delta meson mainly affects
the symmetry energy and through this the chemical composition of a neutron
star. As the effective nucleon mass contributes to hadron chemical potentials
it alters the chemical composition of the star. In the result the obtained
model of the star not only excludes large population of hadrons but also does
not reduce significantly lepton contents in the star interior.Comment: 22 pages, revtex4, 13 figure
The nucleon and mesons effective masses in the Relativistic Mean-Field Theory
Nucleon and meson effective masses in the nonlinear Relativistic Mean - Field
Theory (RMF) introducing a nonlinear omega - rho and sigma coupling motivated
by the Quark Meson Coupling model (QMC) is explored. It is shown that, in
contrast to the usual Walecka model, not only the effective nucleon mass
m_{eff,N} but also the effective sigma, rho meson masses (m_{eff, sigma},
m_{eff, rho}) and the effective omega meson mass m_{eff, omega} are nucleon
density dependent.Comment: 11 pages, iop latex2e, 7 colour figures, revised version of
nucl-th/0011084, accepted to Journal of Physics G: Nuclear and Particle,
presented on "Mesons & Light Nuclei '01", Prague, June 200
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