The Feynman-Metropolis-Teller treatment of compressed atoms has been recently generalized to relativistic regimes and applied to the description of static and rotating white dwarfs in general relativity. We present here the extension of this treatment to the case of finite temperatures and construct the corresponding equation of state (EOS) of the system; applicable in a wide regime of densities that includes both white dwarfs and neutron star outer crusts. We construct the massradius relation of white dwarfs at finite temperatures obeying this new EOS and apply it to the analysis of ultra low-mass white dwarfs with M 0.2M⊙. In particular, we analyze the case of the white dwarf companion of PSR J1738+0333. The formulation is then extrapolated to compressed nuclear matter cores of stellar dimensions, systems with mass numbers A ≈ (m Planck /mn) 3 or mass Mcore ≈ M⊙, where m Planck and mn are the Planck and the nucleon mass. For T ≪ mec 2 /kB ≈ 5.9 × 10 9 K, a family of equilibrium configurations can be obtained with analytic solutions of the ultra-relativistic Thomas-Fermi equation at finite temperatures. Such configurations fulfill global but not local charge neutrality and have strong electric fields on the core surface. We find that the maximum electric field at the core surface is enhanced at finite temperatures with respect to the degenerate case.

We study the thermal evolution of neutron stars containing deconfined quark matter in their core. Such objects are generally referred to as quark-hybrid stars. The confined hadronic matter in their core is described in the framework of non-linear relativistic nuclear field theory. For the quark phase we use a non-local extension of the SU(3) Nambu Jona-Lasinio model with vector interactions. The Gibbs condition is used to model phase equilibrium between confined hadronic matter and deconfined quark matter. Our study indicates that high-mass neutron stars may contain between 35 and 40% deconfined quark-hybrid matter in their cores. Neutron stars with canonical masses of around 1.4 M⊙ would not contain deconfined quark matter. The central proton fractions of the stars are found to be high, enabling them to cool rapidly. Very good agreement with the temperature evolution established for the neutron star in Cassiopeia A (Cas A) is obtained for one of our models (based on the popular NL3 nuclear parametrization), if the protons in the core of our stellar models are strongly paired, the repulsion among the quarks is mildly repulsive, and the mass of Cas A has a canonical value of 1.4 M⊙.

There is solid observational evidence on the existence of massive, M ∼ 1 M , highly magnetized white dwarfs (WDs) with surface magnetic fields up to B ∼ 10 9 G. We show that, if in addition to these features, the star is fast rotating, it can become a rotation-powered pulsar-like WD and emit detectable high-energy radiation. We infer the values of the structure parameters (mass, radius, moment of inertia), magnetic field, rotation period and spin-down rates of a WD pulsar death-line. We show that WDs above the death-line emit blackbody radiation in the soft X-ray band via the magnetic polar cap heating by back flowing pair-created particle bombardment and discuss as an example the X-ray emission of soft gamma-repeaters and anomalous X-ray pulsars within the WD model.

Globally neutral neutron stars, obtained from the solution of the called Einstein-Maxwell-ThomasFermi equations that account for all the fundamental interactions, have been recently introduced. These configurations have a more general character than the ones obtained with the traditional Tolman-Oppenheimer-Volkoff, which impose the condition of local charge neutrality. The resulting configurations have a less massive and thinner crust, leading to a new mass-radius relation. Signatures of this new structure of the neutron star on the thermal evolution might be a potential test for this theory. We compute the cooling curves by integrating numerically the energy balance and transport equations in general relativity, for globally neutral neutron stars with crusts of different masses and sizes, according to this theory for different core-crust transition interfaces. We compare and contrast our study with known results for local charge neutrality. We found a new behavior for the relaxation time, depending upon the density at the base of the crust, ρcrust. In particular, we find that the traditional increase of the relaxation time with the crust thickness holds only for configurations whose density of the base of the crust is greater than ≈ 5 × 10 13 g cm −3 . The reason for this is that neutron star crusts with very thin or absent inner crust have some neutrino emission process blocked which keep the crust hotter for longer times. Therefore, accurate observations of the thermal relaxation phase of neutron stars might give crucial information on the core-crust transition which may aid us in probing the inner composition/structure of these objects.

É inquestionável o sucesso do Mestrado Nacional Profissional em Ensino de Física na melhoria do Ensino de Física na Educação Básica, no entanto seus impactos também podem ser percebidos na Educação Superior. Esta carta ao editor pretende destacar a importância deste Mestrado através do impacto nas publicações de pesquisas desenvolvidas no estado do Tocantins.

Esta é uma breve nota ao editor, em função do importante marco de 2019 para a Revista Brasileira de Ensino de Física (RBEF), por se tratar do seu aniversário de 40 anos. Em função dessa referência e do aumento de pesquisas envolvendo a representatividade feminina nas Ciências no âmbito acadêmico, os autores dessa carta realizaram um mapeamento do perfil das autorias dos artigos científicos na revista ao longo desses 40 anos. Percebe-se, com base nos dados apresentados, o aumento da participação feminina como autoras de trabalhos e um amplo espaço para crescimento.

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