Accretion-Induced Collapse of White Dwarfs as an Alternative Symbiotic Channel to Millisecond Pulsars

Abstract: Recently, extra motivation has been given to the investigations of an unresolved problem of millisecond pulsars (MSPs) produced by the recycling process, as an apparent role of the accretion-induced collapse (AIC) in white dwarfs (WDs) was suggested to this concern. I have found that the distribution of the orbital periods of binary MSPs in the Galactic disk closely follows an exponential distribution. I have also determined the best-fit mean value of Nobs by fitting our data with an exponential distribution for the MSP population. As a result, it can be stated that reaching the Chandrasekhar limit may cause an explosion of a massive WD as a Type Ia supernova (in the case of a CO WD) or an ignition of a ONeMg WD, and possibly merging in some CO WDs, all resulting in peculiar MSP systems. A possible formation scenario, where the system has a circular orbit during this evolutionary stage, is discussed.