Active Luminous Blue Variables in the Large Magellanic Cloud

BARBÁ, R. H.; WALBORN N.; ANGELONI R.; MORRELL N. I.; FERNANDEZ LAJUS E; GAMEN R.C.

ASTRONOMICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 2017 vol. 154 p. 1 - 26

0004-6256

We present extensive spectroscopic and photometric monitoring of two fa-mous and currently highly active LBVs in the LMC, together with more limited coverage of three further, less known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca II] emission lines, as its spectral type becomes unprecedentedly late. Moreover, we have discovered a He II λ4686 emission line in its spectrum that varied in both intensity and velocity within a few months preceding the current outburst, reminiscent of the periastron passage in η Carinae. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are HDE 269582, now a ?second R127? that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216 that changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail andtheir extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse; one of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.