The Neutron Star Zoo

Abstract

Since their discovery 50 years ago, neutron stars have continually astonished. From the first-discovered radio pulsars to the powerful “magnetars” that emit sudden bursts of X-rays and γ-rays, from the so-called Isolated Neutron Stars to Central Compact Objects, observational manifestations of neutron stars are surprisingly varied, with most properties totally unpredicted. The challenge is to cement an overarching physical theory of neutron stars and their birth properties that can explain this great diversity. Here I briefly survey the disparate neutron star classes, describe their properties, highlight recent results, and describe efforts at “grand unification” of this wealth of observational phenomena.

On the role of magnetic fields into the dynamics and gravitational wave emission of binary neutron stars

“…For the analysis in this section, we consider again two BNS systems, one with equal masses of M 1 = M 2 = 1.4 M and other with masses M 1 = 1.8 M , M 2 = 1 M . We consider magnetic fields with strength between B = 10 12 G and B = 8 × 10 16 G, consistent with the values and predictions reported in [10,13]. These magnitudes of the magnetic field imply that the parameter b is within the interval −4.77 × 10 69 g cm 5 /s 2 < b < 4.77 × 10 69 g cm 5 /s 2 .…”

“…In IV B we analyse qualitatively and quantitatively the effect of the presence of magnetic dipole moments with magnetic field strength ranging from B ∼ 10 12 G to B ∼ 10 16 G on some relevant inspiral variables. This strength lies well into the range of systems described in references [10,13]. In IV C, we use the gravitational luminosity and the logarithmic rate of change of orbital period of the event GW170817 to show that given the uncertainly in the mass determination from observational data, it is possible to get a bound for the maximum value of the magnetic field strength such that the mass derived from the magnetized case is still consistent with the observations.…”

“…This model is frequently used to explain the pulsar phenomenon [8]. Highly magnetized rotating NS are characterized by spin periods typically between P ∼ (10 −3 − 12)s and with a change in time of dP dt ∼ (10 −16 − 10 −12 )ss −1 [9,10]. These approximations are consistent with magnetic fields on the surface of pulsars of the order of B ∼ 10 11 − 10 13 G [11,12], or as high as B ∼ 10 14 − 10 15 G in magnetars [13], and even up to 10 16 G are values likely to be found in new born NS [14].…”