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Lookup NU author(s): Dr Dominic BowmanORCiD
Recent photometric observations of massive stars have identified a low-frequency power excess which appears as stochastic low-frequency variability in light-curve observations. We present the oscillation properties of high-resolution hydrodynamic simulations of a star performed with the PPMstarcode. The model star has a convective core mass of and approximately half of the envelope simulated. From this simulation, we extract light curves from several directions, average them over each hemisphere, and process them as if they were real photometric observations. We show how core convection excites waves with a similar frequency as the convective time-scale in addition to significant power across a forest of low and high angular degree l modes. We find that the coherence of these modes is relatively low as a result of their stochastic excitation by core convection, with lifetimes of the order of 10s of days. Thanks to the still significant power at higher l and this relatively low coherence, we find that integrating over a hemisphere produces a power spectrum that still contains measurable power up to the Brunt–Väisälä frequency. These power spectra extracted from the stable envelope are qualitatively similar to observations, with the same order of magnitude yet lower characteristic frequency. This work further shows the potential of long-duration, high-resolution hydrodynamic simulations for connecting asteroseismic observations to the structure and dynamics of core convection and the convective boundary.
Author(s): Thompson W, Herwig F, Woodward PR, Mao H, Denissenkov P, Bowman DM, Blouin S
Publication type: Article
Publication status: Published
Journal: Monthly Notices of the Royal Astronomical Society
Year: 2024
Volume: 531
Issue: 1
Pages: 1316-1337
Print publication date: 01/05/2024
Online publication date: 01/05/2024
Acceptance date: 26/04/2024
Date deposited: 06/12/2024
ISSN (print): 0035-8711
ISSN (electronic): 1365-2966
Publisher: Oxford University Press
URL: https://doi.org/10.1093/mnras/stae1162
DOI: 10.1093/mnras/stae1162
Data Access Statement: 3D and spherically averaged 1D simulation outputs are available at https://www.ppmstar.org along with PYTHON notebooks that have been used to create plots in this paper.
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