The Structure and Signals of Neutron Stars, from Birth to Death

Formation and evolution of pulsars via the accretion induced collapse of white dwarfs

Not scheduled

15m

Speaker

Dr Ali Taani (Al-Balqa' Applied University- Aqaba University College)

Description

The Recycling process is usually considered as a standard model to produce Millisecond Pulsars (MSPs).I will discuss another possible channel involving the Accretion Induced Collapse (AIC) of a white dwarf (WD) in binaries. As accreting binaries lead to orbit circularization due to tidal coupling during the accretion phase, Low-Mass X-Ray Binaries (LMXBs) and Cataclysmic Variable-type binaries (CVs) are considered to be the progenitors of MSPs with very short orbital periods (Porb < 2 d) and highly circular orbits (e < 0.1). I will investigate the progenitors of MSPs with a distribution of long orbital periods, to show the link between WD binaries and long orbits for some binary MSPs. For this task, I will present a study that combines different compact objects in binaries. Knowledge about the values of the orbital parameters (P_orb) and spin periods (P_spin) of these binaries might be useful for understanding the evolutionary history of the systems. I also present a model that attempts to turn binary MSPs into wide binaries with high eccentricities, because of the asymmetric kick imparted to the pulsar during its birth in a supernova. If the system survives, the resulting system typically has an eccentric orbit with a long orbital period. Or it may disrupt the system and create a single MSP. For this reason, massive CV-type binaries provide an alternative link between AIC and MSPs.