2025ApJ...982...12R

We present supernova (SN) 2023ufx, a unique Type IIP SN with the shortest known plateau duration (t_PT ∼ 47 days), a luminous V-band peak (M_V = -​​​​​​18.42 ± 0.08 mag), and a rapid early decline rate (s1 = 3.47 ± 0.09 mag (50 days)^–1). By comparing observed photometry to a hydrodynamic MESA+STELLA model grid, we constrain the progenitor to be a massive red supergiant with M_ZAMS ∼ 19-25 M_⊙. Independent comparisons with nebular spectral models also suggest an initial He-core mass of ∼6 M_⊙, and thus a massive progenitor. For a Type IIP, SN 2023ufx produced an unusually high amount of nickel (⁵⁶Ni) ∼0.14 ± 0.02 M_⊙, during the explosion. We find that the short plateau duration in SN 2023ufx can be explained with the presence of a small hydrogen envelope (${M}_{{{\rm{H}}}_{\mathrm{env}}}$ ∼ 1.2 M_⊙), suggesting partial stripping of the progenitor. About ∼0.09 M_⊙ of circumstellar material through mass loss from late-time stellar evolution of the progenitor is needed to fit the early time (≲10 days) pseudo-bolometric light curve. Nebular line diagnostics of broad and multipeak components of [O I] λλ6300, 6364, Hα, and [Ca II] λλ7291, 7323 suggest that the explosion of SN 2023ufx could be inherently asymmetric, preferentially ejecting material along our line of sight.