2022MNRAS.515.3597L

All Type IIn supernovae (SNe IIn) show narrow hydrogen emission lines in their spectra. Apart from this common feature, they demonstrate very broad diversity in brightness, duration, and morphology of their light curves, which indicates that they likely come from a variety of progenitor systems and explosion channels. A particular subset of SNe IIn, the so-called SNe IIn-P, exhibit ∼100 d plateau phases that are very similar to the ones of the ordinary hydrogen-rich SNe (SNe II). In the past, SNe IIn-P were explained by the models of sub-energetic electron capture explosions surrounded by dense extended winds. In this work, we attempt to explain this class of SNe with standard red supergiant progenitors that experience outbursts several months before the final explosion. The outburst energies that show the best agreement between our models and the data ($5\times 10^{46}\, {\rm erg}$) fall at the low range of the outburst energies that have been observed for SNe IIn (between few times $10^{46}\, {\rm erg}$ and $10^{49}\, {\rm erg}$). Instead, the inferred explosion energy of SN 2005cl is relatively high ($1{-}2\times 10^{51}\, {\rm erg}$) compared to the explosion energies of the ordinary SNe II. Our models provide alternative explanation of SNe IIn-P to the previously proposed scenarios.