Spitzer Space Telescope - General Observer Proposal #3413 Kepler's SNR at 400 Years: A Dust Processing Laboratory Principal Investigator: William Blair Institution: Johns Hopkins University Co-Investigators: Ravi Sankrit, Johns Hopkins University Parviz Ghavamian, Johns Hopkins University Kazimierz Borkowski, North Carolina State University Stephen Reynolds, North Carolina State University Knox Long, Space Telescope Science Institute Science Category: evolved stars/pn/sne Observing Modes: IracMap MipsPhot MipsSed Hours Approved: 5.6 Abstract: We propose MIPS and IRAC imaging and MIPS SED spectroscopy of Kepler's supernova remnant to study the characteristics of dust and the spatial variations of that dust between various well-defined parts of the remnant. The key regions of the SNR include the NW region (dominated by shocked circumstellar and interstellar material), the bright X-ray/radio northern arc (where shocked ejecta and an apparent reverse shock are prevalent), the SE limb (dominated by synchrotron emission), and the central region (which could in principle hide unshocked cold ejecta). The combination of MIPS and IRAC imaging, especially when combined with multiwavelength data sets, will permit us to study hot and cold dust components and their spatial variation, and observe or place limits on IR sychrotron emission. A key question we will answer is whether IR dust signatures in Kepler's SNR arise in shocked ISM, ejecta, or both, and what the total mass of dust is. This latter point will help determine the precursor star and SN type for the Kepler supernova. If the dust emission is indeed dominated by swept-up ISM dust, we will be able to study dust grain destruction behind the primary shock front by comparing the MIPS and IRAC morphologiesi to dust models. MIPS SED R=20 spectra will assess the presence of any strong shock cooling lines such as [OI] 63 um and allow any impacts on the imaging data to be assessed.