3951 20190128153251.0 10.1093/mnras/sty308 DOI SCART-2019-0084 Aerts, C. K2 photometry and HERMES spectroscopy of the blue supergiant ρ Leo: rotational wind modulation and low-frequency waves 2018 We present an 80-d long uninterrupted high-cadence K2 light curve of the B1Iab supergiant ρ Leo (HD 91316), deduced with the method of halo photometry. This light curve reveals a dominant frequency of frot = 0.0373 d−1 and its harmonics. This dominant frequency corresponds with a rotation period of 26.8 d and is subject to amplitude and phase modulation. The K2 photometry additionally reveals multiperiodic low-frequency variability (<1.5 d−1) and is in full agreement with low-cadence high-resolution spectroscopy assembled during 1800 d. The spectroscopy reveals rotational modulation by a dynamic aspherical wind with an amplitude of about 20 km s−1 in the H α line, as well as photospheric velocity variations of a few km s−1 at frequencies in the range 0.2–0.6 d−1 in the Si iii 4567 Å line. Given the large macroturbulence needed to explain the spectral line broadening of the star, we interpret the detected photospheric velocity as due to travelling superinertial low-degree large-scale gravity waves with dominant tangential amplitudes and discuss why ρ Leo is an excellent target to study how the observed photospheric variability propagates into the wind. NO asteroseismology techniques: photometric techniques: spectroscopic stars: massive stars: oscillations stars: rotation Bowman, D. M. Símon-Díaz, S. Buysschaert, B. Johnston, C. Moravveji, E. Beck, P. G. De Cat, P. Triana, S. Aigrain, S. Castro, N. Huber, D. White, T. Monthly Notices of the Royal Astronomical Society 476 2018 1 1234-1241 peter.decat@observatoire.be https://academic.oup.com/mnras/article/476/1/1234/4848277 published in REFERD