On Companion-Induced Off-Center Supernova-Like Explosions

Abstract

We suggest that a neutron star with a strong magnetic field, spiraling into the envelope of a companion star, can generate a ``companion induced SN-like off-center explosion". The strongly magnetized neutron star ("magnetar") is born in a supernova explosion before entering into an expanding envelope of a supergiant companion. If the neutron star collapses into a black hole via the hypercritical accretion during the spiral-in phase, a rapidly rotating black hole with a strong magnetic field at the horizon results. The Blandford-Znajek power is sufficient to power a supernova-like event with the center of explosion displaced from the companion core. The companion core, after explosion, evolves into a C/O-white dwarf or a neutron star with a second explosion. The detection of highly eccentric black-hole, C/O-white dwarf binaries or the double explosion structures in the supernova remnants could be an evidence of the proposed scenario.