A 3D numerical model for Kepler's supernova remnant

Abstract

We present new 3D numerical simulations for Kepler´s supernova remnant. In this work we revisit the possibility that the asymmetric shape of the remnant in X-rays is the product of a type Ia supernova explosion which occurs inside the wind bubble previously created by an AGB companion star. Due to the large peculiar velocity of the system, the interaction of the strong AGB wind with the interstellar medium results in a bow shock structure. In this new model we propose that the AGB wind is anisotropic, with properties such as mass-loss rate and density having a latitude dependence, and that the orientation of the polar axis of the AGB star is not aligned with the direction of motion. The ejecta from the type Ia supernova explosion is modeled using a power-law density prole, and we let the remnant evolve for 400 yr. We computed synthetic X-ray maps from the numerical results. We find that the estimated size and peculiar X-ray morphology of Kepler´s SNR are well reproduced by considering an AGB mass-loss rate of 10-5 M_sol yr-1, a wind terminal velocity of 10 km s-1, an ambient medium density of 10-3 cm^3 and an explosion energy of 7x10^50 erg. The obtained total X-ray luminosity of the remnant in this model reaches 6x10^50 erg, which is within a factor of two of the observed value, and the time evolution of the luminosity shows a rate of decrease in recent decades of ~2.4% yr-1 that is consistent with the observations.