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tokens: determine whether the remnant continues to migrate in the HR diagram towards the hotter S Dor instability strip occupied by quiescent LBVs, or if increasing extinction from ongoing dust condensation in the ejecta pushes it redwards again. Figure 10. Modification of the HR diagram for LBVs and their kin from Mauerhan et al. ( 2015 , see their fig. 8). The magenta coloured square is the previous estimate for the precursor star from Mauerhan et al. ( 2015 ), uncorrected for possible circumstellar extinction. The red square represents the revised best-matching model of the precursor SED, corrected for grey circumstellar extinction (see the text). The blue square indicates the aftermath of the eruption, a hot B4–B5 supergiant, also corrected for grey circumstellar extinction. The luminosities of the remnant and the revised precursor were calculated by integrating the UV–IR SEDs of the best-matching models shown in Figs 8 and 9 . The revised parameters of the stellar precursor warrant re-analysis of the star's initial mass as well, which was previously estimated at ∼30 M ⊙ (Mauerhan et al. 2015 ). Fig. 11 shows the data, after correcting for the purported grey circumstellar extinction parameters discussed above (for the remnant, E ( B − V ) = 0.48 mag and R V = 5.4; for the precursor, E ( B − V ) = 0.16 mag and R V = 5.4), along with evolutionary tracks from the Geneva rotating stellar models for 50 and 60 M ⊙ (Ekström et al. 2012 ); the data appear to most closely match (but are slightly below) the 60 M ⊙ model, which at the locations of both the remnant and precursor is undergoing core-He burning (Ekström et al. 2012 ). This revised initial mass is approximately twice as high as the circumstellar extinction-free estimate by Mauerhan et al. ( 2015 ). Interestingly, the photometry of the remnant and precursor, which was corrected for different values of circumstellar extinction and based on the best SED matches, is consistent with no significant change in stellar luminosity between before and after the 2014 eruption. Figure 11. The precursor (open black square) and remnant (filled black square) photometry of SN Hunt 248 on the HR diagram, after correcting for our estimated circumstellar extinction parameters (see the text, Section 4.1.2 ). The evolutionary tracks are from Geneva rotating stellar models (Ekström et al. 2012 ) at solar metallicity for initial masses of 50 M ⊙ (green curve) and 60 M ⊙ (magenta curve). 4.2 The 2014 outburst, revisited 4.2.1 Massive binary merger-burst? The energy source of the 2014 eruption is uncertain. The structure of the outburst light curve, the outflow velocity and the large-amplitude pre-outburst variability detected over prior decades might provide clues. We can speculate that the cool-hypergiant precursor was a massive interacting binary, perhaps similar to HR 5171 (Chesneau et al. 2014a ), and that its large pseudophotosphere was the signature of a common envelope. If this is the case, it is plausible that SN