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Kepler's supernova remnant (SNR) is believed to result from a Type Iasupernova, but be interacting with dense circumstellar material (CSM), whichmakes its progenitor system a mystery. Using the Chandra ACIS-S 741 kseffective exposure data and an advanced adaptive binning algorithm, we analysethe spectra from tessellated regions in Kepler's SNR. For the first time, wemap out the detailed spatial distributions of emission measure (EM), electrontemperature, ionization parameter, and metal abundances for both the low- andhigh-temperature plasma components. The low-temperature plasma diverges intotwo branches in the temperature v.s. ionization parameter diagram, which appearto be spatially associated with the warm CSM dusts and the Si- and S-richejecta, respectively. We construct the probability distribution functions ofabundance ratios of O and Mg to L-shell emitting Fe ([O]/[Fe]$_{\rm L}$ and[Mg]/[Fe]$_{\rm L}$), and fit them with double Gaussians. Thereby, wedistinguish the CSM from the ejecta: the CSM is characterized by [O]/[Fe]$_{\rmL}$ $= 0.77^{+0.30}_{-0.23}$ and [Mg]/[Fe]$_{\rm L}$ $= 1.11^{+0.46}_{-0.32}$,while the ejecta by [O]/[Fe]$_{\rm L}$ $= 0.31^{+0.17}_{-0.10}$ and[Mg]/[Fe]$_{\rm L}$ $= 0.38^{+0.36}_{-0.19}$. We estimate the total hydrogenmass of the shocked CSM as $\sim 1.4 M_\odot$ and the EM-weighted mean [Mg]/[O]$= 1.14 \pm 0.49$, which can be reproduced with an asymptotic giant branchdonor star with initial mass of $\sim 4 M_\odot$. The abundance ratios from theshocked ejecta are well compatible with the predicted results from sphericaldelayed-detonation models for Type Ia supernovae. We also find that the two`ears' of the remnant are dominated by Si- and S-rich ejecta, thus favoring apre-explosion jets scenario.

Spatially Resolved X-ray Spectroscopy of Kepler's Supernova Remnant: Distinct Properties of the Circumstellar Medium and the Ejecta