2026ApJ...999...93D

We present a detailed photometric and spectroscopic analysis of the Type IIP supernova (SN) SN 2023zcu, which exploded in the galaxy NGC 2139 (redshift z = 0.006). SN 2023zcu exhibits a well-sampled light curve covering the rise, plateau, and nebular phases. It has an optically thick phase of 100.6 ± 0.6 days with a magnitude drop of ∼1.7 mag in the V band during the transition between the plateau and nebular phases. Weak emission features in the early-time spectra indicate a low-level interaction between circumstellar material and the SN ejecta. The spectral evolution is well sampled and exhibits a prominent P Cygni profile of Hα, a defining characteristic of Type IIP SNe. Signatures of metal-line formation (e.g., Fe II, Ca II near-infrared triplet) are also evident in the spectra as the SN evolves. Spectral modeling with the radiative transfer code TARDIS during the early photospheric phase (8.7-35.5 days since explosion) yields photospheric temperatures decreasing from ∼9000 to ∼6000 K and expansion velocities declining from ∼10,000 to ∼5400 km s^–1. A tailored expanding photosphere method fit based on the TARDIS models provides a distance estimate of 27.8 ± 2.0 Mpc. Nebular-phase spectra and bolometric light-curve modeling suggest a progenitor mass in the range 12-15 M_⊙. This thorough analysis helps to constrain progenitor properties and explosion parameters, thereby strengthening our understanding of Type IIP SNe.