The Death of a Star: Spectra From 19 Hours Before Type Ib Supernova (SN 2019ehk) Indicates Wolf-Rayet Progenitor

The last few stages prior to the explosion of a star happen very quickly, on the order of a day, making studying this final state before a supernova explosion difficult. Luckily, SN 2019ehk had a serendipitous spectra from the Very Large Telescope/MUSE taken about 19 hours prior to explosion. The data has a spatial resolution of about 20 pc and a spectra resolution of 2.3 Å. We were able to identify ionized nitrogen and neutral hydrogen emission in near equal parts. We also see minimal variability of the progenitor over the previous 3 years, observed at 11 epochs with Spitzer/IRAC. From this data, we believe that the progenitor of SN 2019ehk is a cool Wolf-Rayet.