Protoquark stars: stability windows and magnetic field effects

Débora Peres Menezes,Verônica Dexheimer,James Rudinei Torres

doi:10.1051/epjconf/20146607020

Débora Peres Menezes, Verônica Dexheimer + Show 1 more

Open Access

https://doi.org/10.1051/epjconf/20146607020

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Abstract

Recently the measurement of (at least) two very massive neutron stars plus the theoretical predictions related to the effects of magnetic fields on the QCD phase diagram shed a new light on the possibility that magnetars can be constituted of deconfined quark matter only. In this work we revisit the conditions for stable quark matter by investigating stability windows for different models at zero and finite temperature and checking the resulting stellar macroscopic properties. Once magnetic fields are considered, investigating anisotropy in the pressure becomes mandatory and this topic is also considered.

Highlights

The influence of strong magnetic fields on the QCD phase diagram is a topic of intense investigations both with lattice and effective model calculations
The whole T − μ plane was studied [1] with the Nambu–Jona-Lasinio model [2] and it was shown that the first order segment of the transition line becomes longer as the field strength increases so that a larger coexistence region for hadronic and quark matter should be expected for strong magnetic fields
−. 8π In Fig. 2 we show the differences in both pressures for matter only, and when the contribution from the pure magnetic field is included for the three snapshots mentioned above labeled i) S /A = 1, ii) S /A = 2 and iii) S /A = 0, except that for S /A = 2 no neutrinos are considered either

Summary

Introduction

The influence of strong magnetic fields on the QCD phase diagram is a topic of intense investigations both with lattice and effective model calculations. Known as magnetars, do not fit into any of these categories They are normally isolated neutron stars whose main power source is in the magnetic field and two classes have been discovered: the soft gamma-repeaters that are x-ray transient sources and the anomalous x-ray pulsars, a class of persistent x-ray sources with no sign of a binary companion. Magnetars are extremely magnetized neutron stars, with magnetic fields reaching B = 1015 G at the surface and central magnetic fields that could reach even higher values [3] When the MIT model is considered, the quark masses are fixed

Stability windows and magnetic field effects

Conclusions