Daryel Manreza Paret

Maximum mass of magnetic white dwarfs

We revisit in this work the problem of the maximum masses of magnetized White Dwarfs (WD). The impact of a strong magnetic field onto the structure equations is addressed. The pressures become anisotropic due to the presence of the magnetic field and split into a parallel and perpendicular components. We first construct stable solutions of TOV equations for the parallel pressures, and found that physical solutions vanish for the perpendicular pressure when

Anisotropic stellar structure equations for magnetized strange stars

B \gtrsim 10^{13}

RELATIVISTIC URCA PROCESSES IN NEUTRON STARS WITH AN ANTIKAON CONDESATE

G. This fact establishes an upper bound for a magnetic field and the stability of the configurations in the (quasi) spherical approximation. Our findings also indicate that it is not possible to obtain stable magnetized WD with super Chandrasekhar masses because the values of the magnetic field needed for them are higher than this bound. To proceed into the anisotropic regime, we derived structure equations appropriated for a cylindrical metric with anisotropic pressures. From the solutions of the structure equations in cylindrical symmetry we have confirmed the same bound for

On Slowly Rotating Magnetized White Dwarfs

B \sim 10^{13}

Information Theoretical Methods as Discerning Quantifiers of the Equations of State of Neutron Stars

G, since beyond this value no physical solutions are possible. Our tentative conclusion is that massive WD, with masses well beyond the Chandrasekhar limit do not constitute stable solutions and should not exist.

KAON CONDENSATION AND THE NUCLEAR EQUATION OF STATE

The fact that a fermion system in an external magnetic field breaks the spherical symmetry suggests that its intrinsic geometry is axisymmetric rather than spherical. In this work we analyze the impact of anisotropic pressures, due to the presence of a magnetic field, in the structure equations of a magnetized quark star. We assume a cylindrical metric and an anisotropic energy momentum tensor for the source. We found that there is a maximum magnetic field that a strange star can sustain, closely related to the violation of the virial relations.

A RELATIVISTIC EFFECTIVE MODEL WITH PARAMETERIZED COUPLINGS FOR NEUTRON STARS: THE ROLE OF ANTIKAON CONDENSATES

A recently developed effective relativistic theory for nuclear matter is applied to the description of the cooling process of baryon degenerate neutron star matter through neutrino emission considering direct URCA processes. In our approach nucleons and antikaon condensates interact with σ, ω, ρ, δ and ς meson fields. Our results indicate a substantial decrease of the critical threshold density for the URCA process. This is because the presence of these interacting degrees of freedom increase the proportion of protons, producing simultaneously the reduction of the isospin asymmetry in nuclear matter. Our results also indicate that neutron stars with larger masses than MNE ~ 0.9M⊙, which represents the stellar critical threshold (the mass of the neutron star whose baryon central density reached the critical density) would be cooled efficiently and be outside the possibility of observation by heat radiation in a few years.

A RELATIVISTIC EFFECTIVE MODEL WITH PARAMETERIZED COUPLINGS FOR NEUTRON STARS

Rotating magnetized white dwarfs are studied within the framework of general relativity using Hartles formalism. Matter inside magnetized white dwarfs is described by an equation of state of particles under the action of a constant magnetic field which introduces anisotropic pressures. Our study is done for values of magnetic field below

Compact Stars and Magnetized CFL Matter

10^{13}

MAGNETIC FIELD AND TEMPERATURE EFFECTS ON STRANGELETS

G -a threshold of the maximum magnetic field obtained by the cylindrical metric solution- and typical densities of WDs. The effects of the rotation and magnetic field combined are discussed, we compute relevant magnitudes such as the moment of inertia, quadrupole moment and eccentricity.