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

SN 2023axu: A Type IIP Supernova Interacted with a Low-Density Stellar Wind
Zeyi Wang, Jujia Zhang, Qian Zhai, Liping Li, G. Valerin, A. Reguitti, A. Pastorello, Zhenyu Wang, Zeyi Zhao, Tengfei Song, Yongzhi Cai
arXiv:2603.11646v2 Announce Type: replace
Abstract: We present photometric and spectroscopic observations of Type IIP supernova SN 2023axu, spanning $sim$400 d after the explosion. Its light curve is typical of normal SNe IIP, with a V-band peak of $-17.25 pm 0.06$ mag and no early-time excess indicative of strong circumstellar interaction. The early spectra exhibit a distinctive broad “ledge” near 4600 AA. 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 SN synthesized $sim 0.055,M_odot$ of $^{56}$Ni, and nebular spectrum analysis indicates a progenitor mass near $15,M_odot$. SN 2023axu thus exemplifies weak ejecta-wind interaction and highlights the diversity of mass-loss histories and circumstellar environments of SNe II progenitors.arXiv:2603.11646v2 Announce Type: replace
Abstract: We present photometric and spectroscopic observations of Type IIP supernova SN 2023axu, spanning $sim$400 d after the explosion. Its light curve is typical of normal SNe IIP, with a V-band peak of $-17.25 pm 0.06$ mag and no early-time excess indicative of strong circumstellar interaction. The early spectra exhibit a distinctive broad “ledge” near 4600 AA. 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 SN synthesized $sim 0.055,M_odot$ of $^{56}$Ni, and nebular spectrum analysis indicates a progenitor mass near $15,M_odot$. SN 2023axu thus exemplifies weak ejecta-wind interaction and highlights the diversity of mass-loss histories and circumstellar environments of SNe II progenitors.