Photometric Signatures of Internal Gravity Waves In TESS OB Stars

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2023-05
Authors
Yenawine, Mitchell
Major Professor
Kerton, Charles
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Kawaler, Steve
Evans, James
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Abstract
Be stars are a subclass of O and B-type stars that show unusual hydrogen line emission in their spectra, rather than absorption. This phenomenon is believed to arise from the existence of a ‘decretion’ disk formed around the rapidly rotating star. While this is the generally accepted origin of the emission lines, the formation of the disk is still mostly unknown. One possible cause is Internal Gravity Waves (IGWs) which form on the boundary between the star’s convective core and radiative envelope. These waves then propagate toward the surface carrying angular momentum and exciting g-mode pulsations. These waves manifest on the star's surface as an excess in the low-frequency power spectra. To test stellar models of IGW propagation we form a pipeline that utilizes data from the Transiting Exoplanet Survey Satellite (TESS) of OB-type stars. We create light curves of a large sample of OB stars and use the Lomb-Scargle algorithm to form their power spectra. We fit these spectra to a Lorentzian Function which characterizes the observed noise and can be directly compared to stellar models.
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2023