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.