The Red Supergiant Progenitor of Type II Supernova 2024ggi

We present a detailed analysis of the progenitor and its local environment for the recently discovered type II supernova (SN) 2024ggi at a distance of about 6.7~Mpc, by utilizing the pre-explosion images from the Hubble Space Telescope (HST) and \textit{Spitzer} Space Telescope. The progenitor is identified as a red, bright variable star, with absolute \(F814W\)-band magnitudes being \(-\)6.2 mag in 1995 to \(-\)7.2 mag in 2003, respectively, consistent with that of a normal red supergiant (RSG) star. Combining with the historical mid-infrared light curves, a pulsational period of about 379~days can be inferred for the progenitor star. Fitting its spectral energy distribution with stellar spectral models yields the stellar parameters of temperature, radius and bolometric luminosity as \(T_*=3290_{-27}^{+19}\)~K, \(R_*=887_{-51}^{+60}\)~R\(_{\odot}\), and log(\(L\)/L\(_{\odot}\))\(=4.92_{-0.04}^{+0.05}\), respectively. The above parameters indicate that the progenitor of SN 2024ggi is consistent with the stellar evolutionary track of a solar-metallicity massive star with an initial mass of \(13_{-1}^{+1}\)~M\(_{\odot}\). Moreover, our analysis indicates a relatively low mass loss rate (i.e., \(< 3\times10^{-6}\)~M\(_{\odot}\)~yr\(^{-1}\)) for the progenitor compared to that inferred from the flashed spectra and X-ray detection (i.e., $10^{-2}$$-$$ 10$$^{-5}\(~M\)_{\odot}\(~yr\)^{-1}$), implying a significant enhancement in mass loss within a few years prior to the explosion.