2025ApJ...993...28M

We present optical photometry and spectroscopy of SN 2019hnl. Discovered within ∼26 hr of explosion by the ATLAS survey, SN 2019hnl is a typical Type IIP supernova (SN) with a peak absolute V-band magnitude of -16.7 ± 0.1 mag, a plateau length of ∼107 days, and an early decline rate of 0.0086 ± 0.0006 mag (50 days)^–1. We use nebular spectroscopy and hydrodynamic modeling with the SNEC, MESA, and STELLA codes to infer that the progenitor of SN 2019hnl was an M_ZAMS ∼ 11M_⊙ red supergiant, which produced 0.047 ± 0.007M_⊙ of ⁵⁶Ni in the explosion. As a part of our hydrodynamic modeling, we reduced hydrogen envelope mass by scaling the mass loss within the “Dutch” wind scheme to fit our light curve, showing that the progenitor of a relatively typical Type IIP SN may experience partial stripping during their evolution and establish massive (∼0.2M_⊙) circumstellar material environments prior to core collapse.