@article{RamiaramanantsoaMoffatHarmonetal.2018,
  author    = {Ramiaramanantsoa, Tahina and Moffat, Anthony F. J. and Harmon, Robert and Ignace, R. and St-Louis, Nicole and Vanbeveren, Dany and Shenar, Tomer and Pablo, Herbert and Richardson, Noel D. and Howarth, Ian D. and Stevens, Ian R. and Piaulet, Caroline and St-Jean, Lucas and Eversberg, Thomas and Pigulski, Andrzej and Popowicz, Adam and Kuschnig, Rainer and Zoclonska, Elzbieta and Buysschaert, Bram and Handler, Gerald and Weiss, Werner W. and Wade, Gregg A. and Rucinski, Slavek M. and Zwintz, Konstanze and Luckas, Paul and Heathcote, Bernard and Cacella, Paulo and Powles, Jonathan and Locke, Malcolm and Bohlsen, Terry and Chen{\´e}, Andr{\´e}-Nicolas and Miszalski, Brent and Waldron, Wayne L. and Kotze, Marissa M. and Kotze, Enrico J. and B{\"o}hm, Torsten},
  title     = {BRITE-Constellation high-precision time-dependent photometry of the early O-type supergiant zeta Puppis unveils the photospheric drivers of its small- and large-scale wind structures},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {473},
  journal   = {Monthly notices of the Royal Astronomical Society},
  number    = {4},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/stx2671},
  pages     = {5532 -- 5569},
  year      = {2018},
  abstract  = {From 5.5 months of dual-band optical photometric monitoring at the 1 mmag level, BRITE-Constellation has revealed two simultaneous types of variability in the O4I(n)fp star ζ Puppis: one single periodic non-sinusoidal component superimposed on a stochastic component. The monoperiodic component is the 1.78-d signal previously detected by Coriolis/Solar Mass Ejection Imager, but this time along with a prominent first harmonic. The shape of this signal changes over time, a behaviour that is incompatible with stellar oscillations but consistent with rotational modulation arising from evolving bright surface inhomogeneities. By means of a constrained non-linear light-curve inversion algorithm, we mapped the locations of the bright surface spots and traced their evolution. Our simultaneous ground-based multisite spectroscopic monitoring of the star unveiled cyclical modulation of its He ii λ4686 wind emission line with the 1.78-d rotation period, showing signatures of corotating interaction regions that turn out to be driven by the bright photospheric spots observed by BRITE. Traces of wind clumps are also observed in the He ii λ4686 line and are correlated with the amplitudes of the stochastic component of the light variations probed by BRITE at the photosphere, suggesting that the BRITE observations additionally unveiled the photospheric drivers of wind clumps in ζ Pup and that the clumping phenomenon starts at the very base of the wind. The origins of both the bright surface inhomogeneities and the stochastic light variations remain unknown, but a subsurface convective zone might play an important role in the generation of these two types of photospheric variability.},
  language  = {en}
}