Interaction of supernova ejecta with asymmetrical circumstellar matter

Using three independent directions we estimate that the fraction of type Ia supernovae (SNe Ia) exploding inside planetary nebulae (PNe), termed SNIPs, is at least .
(i) Taking the variable sodium absorption lines in some SN Ia to originate in a massive circumstellar matter (CSM), we imply that > of SN Ia occur inside a PN (or a PN descendant), hence classify them as SNIPs.
(ii) We next use results that show that whenever there are hydrogen lines in SN Ia the hydrogen mass in the CSM is large (> 1 M_Sun), hence the explosion is a SNIP.
(iii) We examine the X­ray morphologies of 13 well­resolved close­by SN remnants (SNRs) Ia and derive a crude upper limit, according to which 10-30 of all SNRs Ia possess opposite ear­like features, which we take as evidence of SNIP origin. In a detailed study we performed 3D hydrodynamical modelling simulations of the type Ia supernova remnants Kepler and G1.9+0.3. As well, we explored the possibility of iron ejecta thrown during the supenovova, dubbed "iron bullets", with circumstellar medium. Our results lead us to conclude that the two scenarios most contributing to SNe Ia are the core degenerate and the double degenerate scenarios. Together these two account for > of all SNe Ia.