The Type II supernova SN 2020jfo in M61, implications for progenitor system, and explosion dynamics

We present SN 2020jfo, a Type IIP supernova in the nearby galaxy M61. Optical light curves from Zwicky Transient Facility, complemented with data Swift and near-IR photometry are presented. The 350-day duration bolometric curve exhibits relatively short (~ 65 days) plateau. This implies moderate ejecta mass 5 Msun). A series of spectroscopy is presented, including spectropolarimetric observations. nebular spectra dominated by Halpha but also reveal emission lines oxygen calcium. Comparisons to synthetic indicate an initial progenitor about 12 Msun. Stable nickel spectrum, super-solar Ni/Fe ratio. Several years pre-discovery examined, no signs pre-cursor activity found. Pre-explosion Hubble Space Telescope imaging reveals probable star, detected only reddest band fainter than expected for stars 10 - 15 Msun range, tension analysis LC spectral modeling. two additional core-collapse SNe monitored ZTF, which have Halpha-dominated spectra. illustrates how absence or presence interaction circumstellar material affect both LCs particular II 2020amv has powered CSM interaction, after 40 days when bumpy slowly evolving. late-time show strong structure suggesting thin, dense shell. evolution complex three-horn line profile reminiscent that observed 1998S. 2020jfv poorly constrained early-time LC, shows transition hydrogen-poor IIb IIn, where spectrum light-curve rebrightening Halpha, although intermediate width.