Conditions for jet formation in accreting neutron stars: the magnetic field decay

Accreting neutron stars can produce jets only if they are weakly magnetized (B ~ 10⁸ G). On the other hand, neutron stars are compact objects born with strong surface magnetic fields (B ~ 10¹² G). In this work we study the conditions for jet formation in a binary system formed by a neutron star and a massive donor star once the magnetic field has decayed due to accretion. We solve the induction equation for the magnetic field diffusion in a realistic neutron star crust and discuss the possibility of jet launching in systems like the recently detected Supergiant Fast X-ray Transients.