40,522 research outputs found
All spherically symmetric charged anisotropic solutions for compact star
In the present paper we develop an algorithm for all spherically symmetric
anisotropic charged fluid distribution. Considering a new source function
we find out a set of solutions which is physically well behaved and
represent compact stellar models. A detailed study specifically shows that the
models actually correspond to strange stars in terms of their mass and radius.
In this connection we investigate about several physical properties like energy
conditions, stability, mass-radius ratio, electric charge content, anisotropic
nature and surface redshift through graphical plots and mathematical
calculations. All the features from these studies are in excellent agreement
with the already available evidences in theory as well as observations.Comment: 28 pages, 15 figures, major changes in the text. arXiv admin note:
text overlap with arXiv:1408.5126 by other author
Anisotropic models for compact stars
In the present paper we obtain an anisotropic analogue of Durgapal-Fuloria
(1985) perfect fluid solution. The methodology consists of contraction of
anisotropic factor by the help of both metric potentials and
. Here we consider same as Durgapal-Fuloria (1985)
whereas is that given by Lake (2003). The field equations are solved
by the change of dependent variable method. The solutions set mathematically
thus obtained are compared with the physical properties of some of the compact
stars, strange star as well as white dwarf. It is observed that all the
expected physical features are available related to stellar fluid distribution
which clearly indicate validity of the model.Comment: 18 pages, 13 figures, 4 tables; Published in European Physical
Journal
Generalized model for anisotropic compact stars
In the present investigation an exact generalized model for anisotropic
compact stars of embedding class one is sought for under general relativistic
background. The generic solutions are verified by exploring different physical
aspects, viz. energy conditions, mass-radius relation, stability of the models,
in connection to their validity. It is observed that the model present here for
compact stars is compatible with all these physical tests and thus physically
acceptable as far as the compact star candidates ,
and are concerned.Comment: 19 pages, 12 figures, 3 table
A new model for spherically symmetric anisotropic compact star
In this article we obtain a new anisotropic solution for Einstein's field
equation of embedding class one metric. The solution is representing the
realistic objects such as and . We perform detailed
investigation of both objects by solving numerically the Einstein field
equations under with anisotropic pressure. The physical features of the
parameters depend on the anisotropic factor i.e. if anisotropy is zero
everywhere inside the star then the density and pressures will become zero and
metric turns out to be flat. We report our results and compare with the above
mentioned two compact objects on a number of key aspects: the central density,
the surface density onset and the critical scaling behavior, the effective mass
and radius ratio, the anisotropization with isotropic initial conditions,
adiabatic index and red shift. Along with this we have also made a comparison
between the classical limit and theoretical model treatment of the compact
objects. Finally we discuss the implications of our findings for the stability
condition in relativistic compact star.Comment: 13 pages, 9 figures, 2 table
Where we stand on structure dependence of ISGMR in the Zr-Mo region: Implications on K_\infty
Isoscalar giant resonances, being the archetypal forms of collective nuclear
behavior, have been studied extensively for decades with the goal of
constraining bulk nuclear properties of the equation of state, as well as for
modeling dynamical behaviors within stellar environments. An important such
mode is the isoscalar electric giant monopole resonance (ISGMR) that can be
understood as a radially symmetric density vibration within the saturated
nuclear volume. The field has a few key open questions, which have been
proposed and remain unresolved. One of the more provocative questions is the
extra high-energy strength in the region, which manifested in
large percentages of the sum rule in Zr and Mo above the
main ISGMR peak. The purpose of this article is to introduce these questions
within the context of experimental investigations into the phenomena in the
zirconium and molybdenum isotopic chains, and to address, via a discussion of
previously published and preliminary results, the implications of recent
experimental efforts on extraction of the nuclear incompressibility from this
data.Comment: 9 pages, 7 figures, invited to be submitted to a special issue of
EPJA honoring Prof. P. F. Bortigno
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