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 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_, and log(L/L_)=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_. Moreover, our analysis indicates a relatively low mass loss rate (i.e., < 3×10⁻⁶~M_~yr⁻¹) for the progenitor compared to that inferred from the flashed spectra and X-ray detection (i.e., 10⁻²-$$ 10$$⁻⁵$~M$_{}$~yr$⁻¹$), implying a significant enhancement in mass loss within a few years prior to the explosion.