Assessing the complexity of orbital parameters after asymmetric kick in binary pulsars

Abstract

The dynamical characterization of the Millisecond Pulsar (MSP) parameters is a key issue in understanding these systems. We present an analytical analysis of the orbital parameters of binary MSPs with long periods (Porb>2 d) and circular (e≤ 0.1) orbits, produced by an asymmetric kick model imparted during the Accretion Induced Collapse (AIC) of white dwarfs process. It turns out that the distribution of orbits peaks up to Porb,f≤ 90 d with strong circularization. Considering the different assumptions about the distribution of companion He stars 3M⊙≤Mcom≤5M⊙, the binary will affect the setups of the balance condition of minimum energy. Our analytical approach is just a first approach to the more complete models required for describing all binary parameters after an asymmetric kick. Therefore, we have also run some numerical simulations in order to compare their results with the analytical studies. We aim to initiate a first exploration of the full complexity of the problem, when combining a variable kick time and a variable kick vector direction. Indeed, the numerical simulations show patterns resembling the complex behavior found in chaotic scattering problems. Although we deal with a deterministic problem and bounded orbits, the regular characteristic orbits are found in more realistic phases during the AIC process. In addition, the overall process can show complex behaviors strongly associated with the internal kick mechanisms. This would lead us to identify the nature of regular orbits and their orbital morphology.