Direct detection of progenitor stars in pre-explosion images provides crucial insights into the diverse supernova phenomena. We identify the progenitor of SN 2023ixf, the closest Type-II supernova observed in the past decade, using Keck/NIRC2 adaptive optics imaging and pre-explosion HST/ACS images.
Modeling the HST optical, ground-based near-infrared, and Spitzer IRAC [3.6], [4.5] photometry with the SED of a variable dusty red supergiant (RSG), the progenitor appears to be a cool and luminous RSG of logL=5.1, which stands among the most luminous SN II progenitors, with a dramatic 0.11 dex variation in luminosity over a period of 1100 days. The heavy circumstellar extinction also indicates an enhanced pre-explosion mass loss rate above 10⁻⁴ Msun/year. We find strong evidence for periodic variation of optical depth or effective temperature along with luminosity, a necessary assumption to reproduce the wavelength dependence of the variability, which implies episodic dust production (or evaporation) during radial pulsations. The dense and confined circumstellar material is likely ejected during the last episode of radial pulsation before the explosion.