SN 2022jox: An Extraordinarily Ordinary Type II SN with Flash Spectroscopy

Abstract

We present high-cadence optical and ultraviolet (UV) observations of the Type II supernova (SN), SN 2022jox which exhibits early spectroscopic high-ionization flash features of H i , He ii , C iv , and N iv that disappear within the first few days after explosion. SN 2022jox was discovered by the Distance Less Than 40 Mpc survey ∼0.75 day after explosion with follow-up spectra and UV photometry obtained within minutes of discovery. The SN reached a peak brightness of M _V ∼ −17.3 mag, and has an estimated ^56 Ni mass of 0.04 M _⊙ , typical values for normal Type II SNe. The modeling of the early light curve and the strong flash signatures present in the optical spectra indicate interaction with circumstellar material (CSM) created from a progenitor with a mass-loss rate of $\dot{M}\sim {10}^{-3}{\textstyle {\unicode{x02013}}}{10}^{-2}\text{}{M}_{\odot }\,{{\rm{y}}{\rm{r}}}^{-1}$ . There may also be some indication of late-time CSM interaction in the form of an emission line blueward of H α seen in spectra around 200 days. The mass-loss rate of SN 2022jox is much higher than the values typically associated with quiescent mass loss from red supergiants, the known progenitors of Type II SNe, but is comparable to inferred values from similar core-collapse SNe with flash features, suggesting an eruptive event or a superwind in the progenitor in the months or years before explosion.

Keywords

• Type II supernovae
• Circumstellar matter