Using three independent directions, Danny Tsebrenko and I estimate that the fraction of type Ia supernovae (SNe Ia) exploding inside planetary nebulae (PNe), termed SNIPs, is at least 20%. One method was to examine well-resolved supernova remnants where we identify the morphological feature of two opposite `Ears’. We attribute the Ears to features formed during the planetary nebula phase. Below are images taken from the Chandra SNR Catalog where we marked those with Ears. Paper is on astro-ph.
