The Impact of Type Ia Supernova Explosions on the Companion in a Binary System

Using a simple analytic method, we can calculate the impact effect between the ejecta of a SN Ia and its companion to survey the influence of the initial parameters of the progenitor’s system, which is useful for searching the companion in an explosion remnant. The companion models are obtained from Eggleton’s evolution code. The results are divided into two groups based on the mass-transfer stage. For a given condition, more hydrogen-rich material is stripped from the envelope of a Hertzsprung-gap companion than that of a main-sequence companion, while a larger kick velocity and a larger luminosity are gained for a main-sequence companion. The kick velocity is too low to significantly affect the final spatial velocity of the companion, which is mainly affected by the initial parameters of the progenitor systems. The spatial velocity of the stripped material has an upper limit within the range of 8000–9500 km s $^{-1}$ , which only depends on the total kinetic energy of the explosion. The stripped mass, the ratio of the stripped mass to the companion mass and the kick velocity of the companion all significantly depend on the initial companion mass and the orbital period. Our model may naturally explain the spatial velocity of the star G in the remnant of Tycho’s supernova, while an energy-loss mechanism is needed to interpret its luminosity.