3 research outputs found
Stars in the braneworld
We show that in a Randall-Sundrum II type braneworld, the vacuum exterior of
a spherical star is not in general a Schwarzschild spacetime, but has
radiative-type stresses induced by 5-dimensional graviton effects. Standard
matching conditions do not lead to a unique exterior on the brane because of
these 5-dimensional graviton effects. We find an exact uniform-density stellar
solution on the brane, and show that the general relativity upper bound
is reduced by 5-dimensional high-energy effects. The existence
of neutron stars leads to a constraint on the brane tension that is stronger
than the big bang nucleosynthesis constraint, but weaker than the Newton-law
experimental constraint. We present two different non-Schwarzschild exteriors
that match the uniform-density star on the brane, and we give a uniqueness
conjecture for the full 5-dimensional problem.Comment: 6 pages RevTex, 2 figs, minor corrections to match version to appear
in Phys. Rev.
Particle motion in the field of a five-dimensional charged black hole
In this paper, we have investigated the geodesics of neutral particles near a
five-dimensional charged black hole using a comparative approach. The effective
potential method is used to determine the location of the horizons and to study
radial and circular trajectories. This also helps us to analyze the stability
of radial and circular orbits. The radius of the innermost stable circular
orbits have also been determined. Contrary to the case of massive particles for
which, the circular orbits may have up to eight possible values of specific
radius, we find that the photons will only have two distinct values for the
specific radii of circular trajectories. Finally we have used the dynamical
systems analysis to determine the critical points and the nature of the
trajectories for the timelike and null geodesics.Comment: 15 pages, accepted for publication in Astrophysics and Space Scienc
Electromagnetic Fields of Slowly Rotating Compact Magnetized Stars in Braneworld
We study the structure of electromagnetic field of slowly rotating magnetized
star in a Randall-Sundrum II type braneworld. The star is modeled as a sphere
consisting of perfect highly magnetized fluid with infinite conductivity and
frozen-in dipolar magnetic field. Maxwell's equations for the external magnetic
field of the star in the braneworld are analytically solved in approximation of
small distance from the surface of the star. We have also found numerical
solution for the electric field outside the rotating magnetized neutron star in
the braneworld in dependence on brane tension. The influence of brane tension
on the electromagnetic energy losses of the rotating magnetized star is
underlined. Obtained "brane" corrections are shown to be relevant and have
non-negligible values. In comparison with astrophysical observations on pulsars
spindown data they may provide an evidence for the brane tension and, thus,
serve as a test for the braneworld model of the Universe.Comment: 11 pages, 5 figure