The Center of Expansion and Age of the Oxygen-rich Supernova Remnant 1E 0102.2-7219

Supernova remnants encode valuable information about the explosion processes of supernovae. At optical wavelengths, metal-rich ejecta can be followed over many years to determine the precise origin of the explosion which, in turn, can be used to estimate the remnant’s age. Using four epochs of high resolution Hubble Space Telescope images spanning 19 yr, we present new proper motion measurements of optically emitting oxygen-rich knots of the young Small Magellanic Cloud supernova remnant 1E 0102.2-7219 (E0102). We find a robust center of expansion of α = 1:04:02.48 and δ = -72:01:53.92 (J2000) with 1-σ uncertainty of 1.57" using 45 knots from images obtained with the Advanced Camera for Surveys using the F475W filter in 2003 and 2013 having the highest signal-to-noise ratio. We also estimate an associated explosion age of 1761±177 yr by selecting knots with the highest proper motions, that are assumed to be the least decelerated. We find evidence of an asymmetry in the proper motions of the knots as a function of position angle. We conclude that these asymmetries were most likely caused by interaction between E0102’s original supernova blast wave and an inhomogeneous surrounding environment, as opposed to intrinsic explosion asymmetry. We discuss our findings as they compare to previous age and center of expansion estimates and their relevance to a recently identified candidate central compact object.