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A neutron star was first detected as a pulsar in 1967. It is one of the most mysterious compact objects in the universe, with a radius of the order of 10 km and masses that can reach two solar masses. In fact, neutron stars are star remnants, a kind of stellar zombies (they die, but do not disappear). In the last decades, astronomical observations yielded various contraints for the neutron star masses and finally, in 2017, a gravitational wave was detected (GW170817). Its source was identified as the merger of two neutron stars coming from NGC 4993, a galaxy 140 million light years away from us. The very same event was detected in $gamma$-ray, x-ray, UV, IR, radio frequency and even in the optical region of the electromagnetic spectrum, starting the new era of multi-messenger astronomy. To understand and describe neutron stars, an appropriate equation of state that satisfies bulk nuclear matter properties is necessary. GW170817 detection contributed with extra constraints to determine it. On the other hand, magnetars are the same sort of compact objects, but bearing much stronger magnetic fields that can reach up to 10$^{15}$ G on the surface as compared with the usual 10$^{12}$ G present in ordinary pulsars. While the description of ordinary pulsars is not completely established, describing magnetars poses extra challenges. In this paper, I give an overview on the history of neutron stars and on the development of nuclear models and show how the description of the tiny world of the nuclear physics can help the understanding of the cosmos, especially of the neutron stars.
Context: The Mira variable LX Cyg showed a dramatic increase of its pulsation period in the recent decades and appears to undergo an important transition in its evolution. Aims: We aim at investigating the spectral type evolution of this star over th
We report on the results of a 4-year timing campaign of PSR~J2222$-0137$, a 2.44-day binary pulsar with a massive white dwarf (WD) companion, with the Nanc{c}ay, Effelsberg and Lovell radio telescopes. Using the Shapiro delay for this system, we find
We propose that the observed cooling of the neutron star in Cassiopeia A is due to enhanced neutrino emission from the recent onset of the breaking and formation of neutron Cooper pairs in the 3P2 channel. We find that the critical temperature for th
We report results from a convection dynamo simulation of proto-neutron star (PNS), with a nuclear equation of state (EOS) and the initial hydrodynamic profile taken from a neutrino radiation-hydrodynamics simulation of a massive stellar core-collapse
It is now possible to model thermal relaxation of neutron stars after bouts of accretion during which the star is heated out of equilibrium by nuclear reactions in its crust. Major uncertainties in these models can be encapsulated in modest variation