25 research outputs found
Radial pulsation of a compact object in d dimensions
RESUMEN
The influence of the extra dimensions on the equilibrium and radial pulsation of a compact object is investigated. For such purpose, we solve the stellar structure equations and radial pulsation equations, both modified from their original version to include the extra dimensions (d ≥ 4) taking into account that spacetime outside the object is depicted by a Schwarzschild-Tangherlini metric. In addition, we consider that the pressure and the energy density are connected by a linear relation. Some properties of compact objects are analyzed, such as mass and period of the fundamental mode and their dependencies with the spacetime dimensions. We found that the maximum mass marks the begining of the instability, indicating that in a sequence of equilibrium configurations, the regions constitute by stable and unstable compact objects are distinguished by the relations and , respectively
White dwarfs with a surface electrical charge distribution: Equilibrium and stability
The equilibrium configuration and the radial stability of white dwarfs
composed of charged perfect fluid are investigated. These cases are analyzed
through the results obtained from the solution of the hydrostatic equilibrium
equation. We regard that the fluid pressure and the fluid energy density follow
the relation of a fully degenerate electron gas. For the electric charge
distribution in the object, we consider that it is centralized only close to
the white dwarfs' surfaces. We obtain larger and more massive white dwarfs when
the total electric charge is increased. To appreciate the effects of the
electric charge in the structure of the star, we found that it must be in the
order of with which the electric field is about
. For white dwarfs with electric fields close to the
Schwinger limit, we obtain masses around . We also found that in
a system constituted by charged static equilibrium configurations, the maximum
mass point found on it marks the onset of the instability. This indicates that
the necessary and sufficient conditions to recognize regions constituted by
stable and unstable equilibrium configurations against small radial
perturbations are respectively and .Comment: This is a preprint. The original paper will be published in EPJ
Phase transition and stiffer core fluid in neutron stars: Effects on stellar configurations, dynamical stability, and tidal deformability
In this work, we investigate the influence of the phase transition and a
stiffer fluid in neutron stars' cores on the static equilibrium configuration,
dynamical stability, and tidal deformability. For this aim, it is taken into
account that the fluid in the core and the envelope follow the relativistic
polytropic equation of state. We find that the phase transition and a stiffer
fluid in the core will reflect in the total mass, radius, speed of sound, core
radius, radial stability with a slow and rapid conversion at the interface, and
tidal deformability. We also investigate the dimensionless tidal deformability
and for a binary neutron stars system with chirp mass
equal to GW. Finally, we contrast our results with observational data
to show the role that phase transition and a stiffer core fluid could play in
the study of neutron stars.Comment: To appear in EPJ