BRITEness variations of the BRITEst hot stars

We and our collaborators have been using BRITE-Constellation since the beginning of the mission to observe some of the intrinsically and apparently brightest hot stars in the sky. This includes O stars, luminous blue variables (LBVs) and Wolf-Rayet (WR) stars, which share the feature of driving strong winds and ending in a supernova explosion yielding mainly a black hole, or a neutron star in some cases, or even no remnant at all. As such, O stars and their descendant LBVs and WR stars are tied to gamma-ray bursts and gravitational wave sources, as well as to the first stars to form in the Universe which were predominantly very massive. We present two key cases for O and WR stars observed by BRITE, with their implications for hot star winds and internal structure. In particular, contrary to expectations, hot luminous stars (especially the most extreme among them) tend to show hydrostatic-surface, semi-stable bright spots that betray the stellar rotation. Such bright spots are found to drive large-scale, spiral-shaped, wind features known as co-rotating interaction regions (CIRs), so far regarded as virtually present in all O-star and some WR-star winds. These bright spots are likely the direct result of a distinct layer of subsurface convection, as proposed by recent theoretical investigations. This layer may also be the ultimate source of shorter-lived stochastic perturbations in the photosphere, which are found to drive clumping in the inner part of O-star and very likely also WR winds.