Bibcode
Bowman, D. M.; Aerts, C.; Johnston, C.; Pedersen, M. G.; Rogers, T. M.; Edelmann, P. V. F.; Simón-Díaz, S.; Van Reeth, T.; Buysschaert, B.; Tkachenko, A.; Triana, S. A.
Bibliographical reference
Astronomy and Astrophysics, Volume 621, id.A135, 41 pp.
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1
2019
Journal
Citations
74
Refereed citations
65
Description
Context. Main sequence stars with a convective core are predicted to
stochastically excite internal gravity waves (IGWs), which effectively
transport angular momentum throughout the stellar interior and explain
the observed near-uniform interior rotation rates of intermediate-mass
stars. However, there are few detections of IGWs, and fewer still made
using photometry, with more detections needed to constrain numerical
simulations. Aims: We aim to formalise the detection and
characterisation of IGWs in photometric observations of stars born with
convective cores (M ≳ 1.5 M⊙) and parameterise the
low-frequency power excess caused by IGWs. Methods: Using the
most recent CoRoT light curves for a sample of O, B, A and F stars, we
parameterised the morphology of the flux contribution of IGWs in Fourier
space using an MCMC numerical scheme within a Bayesian framework. We
compared this to predictions from IGW numerical simulations and
investigated how the observed morphology changes as a function of
stellar parameters. Results: We demonstrate that a common
morphology for the low-frequency power excess is observed in early-type
stars observed by CoRoT. Our study shows that a background
frequency-dependent source of astrophysical signal is common, which we
interpret as IGWs. We provide constraints on the amplitudes of IGWs and
the shape of their detected frequency spectrum across a range of mass,
which is the first ensemble study of stochastic variability in such a
diverse sample of stars. Conclusions: The evidence of a
low-frequency power excess across a wide mass range supports the
interpretation of IGWs in photometry of O, B, A and F stars. We also
discuss the prospects of observing hundreds of massive stars with the
Transiting Exoplanet Survey Satellite (TESS) in the near future.
Related projects
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Physical properties and evolution of Massive Stars
This project aims at the searching, observation and analysis of massive stars in nearby galaxies to provide a solid empirical ground to understand their physical properties as a function of those key parameters that gobern their evolution (i.e. mass, spin, metallicity, mass loss, and binary interaction). Massive stars are central objects to
Sergio
Simón Díaz