R71 and an LBV outburst with a distinction

Andrea Mehner, ESO

In 2005, the LBV R71 started its ascent to a new outburst, which may have culminated at the end of 2012 and made R71 the 
visually brightest star in the LMC. The visual amplitude of > 2 mag is the largest recorded in the Local Group of galaxies since 
the giant eruption of eta Car 170 years ago and results from the combination of a fivefold increase in radius to 500 R and a 
drop in Teff by 60% to 6650 K (spectral type F5-F8). Uncertainties in the reddening do not currently permit stringent limits to be 
placed on changes in Lbol. However, the most likely range of 0.4 to 1.3 mag does not bracket the conventional paradigm of 
constant bolometric luminosity during LBV outbursts. While the expansion velocity of the (pseudo-)photosphere remained in the 
range of -130 to -200 kms􀀀1, we infer an increase in mass-loss rate by a factor of 1000 to 5x10􀀀4 Myr􀀀1.