Connecting the progenitors, pre-explosion variability, and giant outbursts of luminous blue variables with Gaia16cfr

Understand

We present multi-epoch, multi-colour pre-outburst photometry and post-outburst light curves and spectra of the luminous blue variable (LBV) outburst Gaia16cfr discovered by the Gaia satellite on 1 December 2016.

• We detect Gaia16cfr in 13 epochs of Hubble Space Telescope imaging spanning phases of 10 yr to 8 months before the outburst and in Spitzer Space Telescope imaging 13 years before outburst.
• Pre-outburst optical photometry is consistent with an 18 Msun F8 I star, although the star was likely reddened and closer to 30 Msun.
• The pre-outburst source exhibited a significant near-infrared excess consistent with a 120 AU shell with 4x10-6 Msun of dust.