In this study we present the results of a five-year follow-up campaign of the
long-lived type IIn supernova SN 2017hcc, found in a spiral dwarf host of
near-solar metallicity. The long rise time (57 ± 2 days, ATLAS o band)
and high luminosity (peaking at −20.78 ± 0.01 mag in the ATLAS o band)
point towards an interaction of massive ejecta with massive and dense
circumstellar material (CSM). The evolution of SN 2017hcc is slow, both
spectroscopically and photometrically, reminiscent of the long-lived type IIn,
SN 2010jl. An infrared (IR) excess was apparent soon after the peak, and
blueshifts were noticeable in the Balmer lines starting from a few hundred
days, but appeared to be fading by around +1200 days. We posit that an IR light
echo from pre-existing dust dominates at early times, with some possible
condensation of new dust grains occurring at epochs >∼+800 days.Comment: Accepted to A&