SN 2023axu: A Type IIP Supernova Interacted with a Low-density Stellar Wind

Abstract We present photometric and spectroscopic observations of Type IIP supernova (SN IIP) SN 2023axu, spanning ∼ 400 days after the explosion. Its light curve is typical of normal SNe IIP, with a V -band peak of −17.25 ± 0.06 mag and no early time excess indicative of strong circumstellar interaction. The early spectra exhibit a distinctive broad “ledge” near 4600 Å. Through spectral modeling and comparison, we attribute this feature to a blend of C, N, and He lines excited by weak interaction between the ejecta and a low-density stellar wind. The late-time photometric evolution shows no discernible contribution from interaction, arguing against strong late-time circumstellar material engagement and supporting the low-density wind scenario. From modeling, this supernova synthesized ∼0.055 M ⊙ of 56 Ni and nebular spectrum analysis indicates a progenitor mass near 15 M ⊙ . SN 2023axu thus exemplifies weak ejecta–wind interaction and highlights the diversity of mass-loss histories and circumstellar environments of SNe II progenitors.