The Interaction of Type Ia Supernovae with Planetary Nebulae: the Case
  of Kepler's Supernova Remnant
  One of the key methods for determining the unknown nature of Type Ia
supernovae (SNe Ia) is the search for traces of interaction between the SN
ejecta and the circumstellar structures at the resulting supernova remnants
(SNRs Ia). So far, the observables that we receive from well-studied SNRs Ia
cannot be explained self-consistently by any model presented in the literature.
In this study, we suggest that the circumstellar medium (CSM) being observed to
surround several SNRs Ia was mainly shaped by planetary nebulae (PNe) that
originated from one or both progenitor stars. Performing two-dimensional
hydrodynamic simulations, we show that the ambient medium shaped by PNe can
account for several properties of the CSM that have been found to surround SNe
Ia and their remnants. Finally, we model Kepler's SNR considering that the SN
explosion occurred inside a bipolar PN. Our simulations show good agreement
with the observed morphological and kinematic properties of Kepler's SNR. In
particular, our model reproduces the current expansion parameter of Kepler's
SNR, the partial interaction of the remnant with a dense CSM at its northern
region and finally the existence of two opposite protrusions (`ears') at the
equatorial plane of the SNR.
