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Lookup NU author(s): Rathish Ratnasingam,
Professor Tamara Rogers
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© 2018 The Author(s). Stochastically triggered photospheric light variations reaching ~40 mmag peak-to-valley amplitudes have been detected in the O8 Iaf supergiant V973 Scorpii as the outcome of 2 months of high-precision time-resolved photometric observations with the BRIght Target Explorer (BRITE) nanosatellites. The amplitude spectrum of the time series photometry exhibits a pronounced broad bump in the low-frequency regime (≲0.9 d-1) where several prominent frequencies are detected. A time-frequency analysis of the observations reveals typical mode lifetimes of the order of 5-10 d. The overall features of the observed brightness amplitude spectrum ofV973 Sco matchwellwith those extrapolated from two-dimensional hydrodynamical simulations of convectively driven internal gravity waves randomly excited from deep in the convective cores of massive stars. An alternative or additional possible source of excitation from a sub-surface convection zone needs to be explored in future theoretical investigations.
Author(s): Ramiaramanantsoa T, Ratnasingam R, Shenar T, Moffat AFJ, Rogers TM, Popowicz A, Kuschnig R, Pigulski A, Handler G, Wade GA, Zwintz K, Weiss WW
Publication type: Article
Publication status: Published
Journal: Monthly Notices of the Royal Astronomical Society
Print publication date: 11/10/2018
Online publication date: 19/07/2018
Acceptance date: 17/07/2018
ISSN (print): 0035-8711
ISSN (electronic): 1365-2966
Publisher: Oxford University Press
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