2018A&A...613A..33C

We performed a spectroscopic and photometric analysis to study new eruptions in two luminous blue variables (LBVs) in the Magellanic Clouds. We detected a strong new eruption in the LBV R40 that reached V∼9.2 in 2016, which is around 1.3mag brighter than the minimum registered in 1985. During this new eruption, the star changed from an A-type to a late F-type spectrum. Based on photometric and spectroscopic empirical calibrations and synthetic spectral modeling, we determine that R 40 reached T_eff=5800-6300K during this new eruption. This object is thereby probably one of the coolest identified LBVs. We could also identify an enrichment of nitrogen and r- and s-process elements. We detected a weak eruption in the LBV R 110 with a maximum of V∼9.9mag in 2011, that is, around 1.0mag brighter than in the quiescent phase. On the other hand, this new eruption is about 0.2mag fainter than the first eruption detected in 1990, but the temperature did not decrease below 8500K. Spitzer spectra show indications of cool dust in the circumstellar environment of both stars, but no hot or warm dust was present, except by the probable presence of PAHs in R 110. We also discuss a possible post-red supergiant nature for both stars.