Bowman, D.M. ; Burssens, S. ; Pedersen, M.G. ; Johnston, C. ; Aerts, C. ; Buysschaert, B. ; Tkachenko, A. ; Rogers, T.M. ; Edelmann, P.V.F. ; Ratnasingam, R.P. ; Simón-Díaz, S. ; Moravveji, E. ; Pope, B.J.S. ; White, T.R. ; De Cat, P.

published in Nature Astronomy, 3, pp. 760-765

Abstract: At the ends of their lives, massive stars explode as supernovae and form a black hole or neutron star. This enriches the interstellar medium with chemical elements and impacts the next generation of stars and galactic evolution. The chemical yield and remnant mass strongly depend on the internal physical properties of the progenitor star which is currently not well understood. The large theoretical uncertainties of massive star interiors accumulate throughout their evolution, and the lack of a robust theory is particularly pertinent for the blue supergiant phase. Stellar oscillations represent a unique method of probing stellar interiors, yet inference for blue supergiants is hampered by a dearth of these objects with identified pulsation modes in space photometry missions. Here we report the detection of diverse pulsational variability in blue supergiants using K2 space mission photometry, and highlight the potential for asteroseismology of these stars. The discovery of coherent pulsation modes and low-frequency internal gravity waves allow us to map the evolution of hot massive stars during the late stages of their lives prior to exploding as supernovae. Future asteroseismic modelling will provide the ages, core masses, interior mixing, rotation properties and angular momentum transport. The discovery of widespread variability in blue supergiants is a new step towards a data-driven empirical calibration of theoretical evolution models for the most massive stars in the Universe.

DOI: 10.1038/s41550-019-0768-1