2021MNRAS.504L..51S

Some hydrogen-poor superluminous supernovae (SLSNe) exhibit bumps in the tails of their light curves associated with hydrogen features in their late time spectra. Here we use the explosion parameters of one such SLSN - SN 2017gci - to search the stellar models of the Binary Population And Spectral Synthesis (BPASS) code for potential progenitors. We find good matches for a 30 M_☉ progenitor star in a binary system and no matches from single-star models. Common envelope and mass transfer after the giant branch, combined with increased mass loss from strong stellar winds immediately before death, allow the progenitor to lose its hydrogen envelope decades before the explosion. This results in a hydrogen poor SLSN and allows for delayed interaction of the ejecta with the lost stellar material.