Spectropolarimetric Evolution of the Type II-Plateau Supernova, SN 2017eaw

The most common type of core-collapse supernovae (SNe) is the Type II-Plateau (II-P), which demonstrably arise from red supergiant progenitor stars [1]. Although traditionally assumed to explode in a spherically symmetric manner, evidence continues to mount that such explosions are inherently asymmetric, and the most direct probe of early-time geometry is the polarization of the supernova’s light. Here we present a preliminary analysis of seven epochs of spectropolarimetry of the Type II-P supernova, SN 2017eaw. The data sample the photospheric phase from days 4 through 111 after the estimated date of explosion (2017 May 12.2 UT; ref. [2]), and were taken as part of the Supernova Spectropolarimetry (SNSPOL) Project [3] using the CCD Imaging/Spectropolarimeter (SPOL) on the 61” Kuiper, 6.5 m MMT, and 90” Bok telescopes. We shall compare the spectropolarimetric evolution of SN 2017eaw against the growing database of similarly observed SNe II-P.

This work was supported by NSF grants AST-1210311 and AST-2010001, and NASA grant NNX15AU81G. References: [1] Smartt, S. J. 2009, ARAA, 47, 63. [2] Van Dyk, S. D. et al. 2019, ApJ, 875. [3] Williams, G. G., et al. 2018, BAAS, 231, 245.07.