A formation scenario for the triple pulsar PSR J0337+1715: Breaking a binary system inside a common envelope

We propose a scenario for the formation of the pulsar with two white dwarfs (WDs) triple system PSR J0337+1715. In our scenario, a close binary system is tidally and frictionally destroyed inside the envelope of a massive star that later goes through an accretion-induced collapse (AIC) and forms the neutron star (NS). The proposed scenario includes a new ingredient of a binary system that breaks up inside a common envelope. We use the BINARY_C software to calculate the post-break-up evolution of the system, and show that both low-mass stars end as helium WDs. One of the two lower mass stars that ends further out, the tertiary star, transfers mass to the ONeMg WD remnant of the massive star, and triggers the AIC. The inner low-mass main-sequence star evolves later, induces AIC if the tertiary had not done it already, and spins-up the NS to form a millisecond pulsar. This scenario is not extremely sensitive to many of the parameters, such as the eccentricity of the tertiary star and the orbital separation of the secondary star after the low-mass binary system breaks loose inside the envelope, and to the initial masses of these stars. The proposed scenario employs an efficient envelope removal by jets launched by the compact object immersed in the giant envelope, and the newly proposed grazing envelope evolution.