The Dusty Progenitor Star of the Type II Supernova 2017eaw

Understand

We present pre-explosion photometry of the likely progenitor star of the Type II supernova (SN II) 2017eaw in NGC 6946.

• We use a Hubble Space Telescope (HST) image of SN 2017eaw to perform relative astrometry with HST and Spitzer Space Telescope (Spitzer) imaging, finding a single point source consistent with its position.
• We detect the progenitor star in $>$40 epochs of HST and Spitzer imaging covering 12.9 years to 43 days before discovery.
• While the progenitor luminosity was roughly constant for most of this period, there was a $\sim$20% increase in its $4.5~\mu$m luminosity over the final 3 years before explosion.