Vol. 628
In section 7. Stellar structure and evolution

A luminous stellar outburst during a long-lasting eruptive phase first, and then SN IIn 2018cnf

by A. Pastorello, A. Reguitti, A. Morales-Garoffolo, et al. 2019, A&A, 628, A93

It is always difficult to shed light on the latest stages of a dying star that blows off like a supernova. Nowadays, we have wide-field optical surveys that monitor the sky every night and collect those data for the ages. When a supernova explodes, one can inspect these archival images by looking for past signs of activity. Very few cases of this pre-explosion activity are currently known. In this paper, the authors reveal an eruptive phase from SN2018cnf, which occured approximately three years before the explosion. This event appears to have formed the circumstellar ambient into which the supernova exploded. Indeed, spectral signatures for the interaction of the supernova ejecta with this medium were observed in the supernova spectra. This indicates that the progenitor is probably a massive hypergiant star.