A 14-year Proper Motion Study Of The Forward Shock Of Kepler’s Supernova Remnant

We present measurements of the expansion of Kepler’s Supernova Remnant (SNR) over three epochs of Chandra X-ray observations from 2000, 2006, and 2014. Kepler’s SNR provides an important opportunity for studying the expansion rate of the forward shock front of a Type Ia supernova. As the remnant of a historical supernova (observed from Earth in 1604 CE), Kepler’s SNR represents a critical step in understanding these cosmic explosions. Combining new data from 2014 with previous epochs in 2000 and 2006, we can observe the proper motion of filaments along the outer rim of the SNR. Prior studies of Kepler’s SNR have shown proper motion differences up to a factor of 3 between northern and southern regions around the remnant. The relatively long baseline between our observations will guarantee smaller uncertainties when we refine these measurements and will help us determine any change in the expansion velocity of the forward shock. Measurements of the asymmetry in forward shock velocity can also provide insight into the nature of the explosion and density of the circumstellar material.