{"publication_identifier":{"issn":["2791-4585"]},"acknowledgement":"I would like to give thanks to myself for my hard work on this document. This paper includes data collected by the Kepler mission and obtained from the MAST data\r\narchive at the Space Telescope Science Institute (STScI). Funding for the Kepler mission is\r\nprovided by the NASA Science Mission Directorate. STScI is operated by the Association of\r\nUniversities for Research in Astronomy, Inc., under NASA contract NAS 5–26555.\r\n","citation":{"mla":"Smith, Kanah. <i>Exploring Internal Magnetism in Partially Suppressed Red Giant Stars</i>. Institute of Science and Technology Austria, 2025, doi:<a href=\"https://doi.org/10.15479/AT-ISTA-19853\">10.15479/AT-ISTA-19853</a>.","ieee":"K. Smith, “Exploring internal magnetism in partially suppressed red giant stars,” Institute of Science and Technology Austria, 2025.","chicago":"Smith, Kanah. “Exploring Internal Magnetism in Partially Suppressed Red Giant Stars.” Institute of Science and Technology Austria, 2025. <a href=\"https://doi.org/10.15479/AT-ISTA-19853\">https://doi.org/10.15479/AT-ISTA-19853</a>.","short":"K. Smith, Exploring Internal Magnetism in Partially Suppressed Red Giant Stars, Institute of Science and Technology Austria, 2025.","apa":"Smith, K. (2025). <i>Exploring internal magnetism in partially suppressed red giant stars</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/AT-ISTA-19853\">https://doi.org/10.15479/AT-ISTA-19853</a>","ista":"Smith K. 2025. Exploring internal magnetism in partially suppressed red giant stars. Institute of Science and Technology Austria.","ama":"Smith K. Exploring internal magnetism in partially suppressed red giant stars. 2025. doi:<a href=\"https://doi.org/10.15479/AT-ISTA-19853\">10.15479/AT-ISTA-19853</a>"},"day":"08","publication_status":"published","department":[{"_id":"GradSch"},{"_id":"LiBu"}],"date_published":"2025-10-08T00:00:00Z","_id":"19853","file_date_updated":"2025-10-09T14:38:57Z","alternative_title":["ISTA Master's Thesis"],"year":"2025","page":"38","status":"public","ddc":["520"],"supervisor":[{"full_name":"Bugnet, Lisa Annabelle","orcid":"0000-0003-0142-4000","last_name":"Bugnet","first_name":"Lisa Annabelle","id":"d9edb345-f866-11ec-9b37-d119b5234501"}],"has_accepted_license":"1","corr_author":"1","abstract":[{"text":"The internal dynamical properties of red giant stars have been explored extensively in recent\r\nyears as a result of the increase in high precision data availability from the space missions\r\nKepler and TESS (Transiting Exoplanet Survey Satellite), and in this exploration, it has been\r\ndiscovered that some of these stars are not behaving as expected. Red giants are stars that have\r\nevolved off of the main sequence after having completed fusing hydrogen into helium in their\r\ncore. Observational data shows that the cores are rotating significantly slower than models can\r\nrecreate consistently across evolutionary stages. This discrepancy has prompted investigation\r\ninto the efficiency of angular momentum transport mechanisms and mixing processes including\r\nmeridional circulation, shear instability, internal gravity waves, Tayler-Spruit dynamo, fossil\r\nmagnetic fields etc., to explain this behavior.\r\nAnalyzing seismic oscillations in stars, via asteroseismology, is a powerful tool as it is the only\r\nway in which the deep stellar interior can be probed and subsequently characterized; this is\r\npossible as global oscillations modulating the stellar surface are effected by internal processes.\r\nFor red giants, p-modes (pressure modes; resonating through the entire star) and g-modes\r\n(gravity-modes; resonating in the radiative interior) couple to create mixed modes. These\r\nmixed modes give access to the otherwise hidden stellar interior as g-modes couple to p-modes,\r\ndelivering information from the interior to the surface.\r\nInternal magnetic signatures have been observationally confirmed in red giant stars via\r\nasteroseismology and characterized in two ways. One being that dipole mixed modes with\r\nℓ = 1 will display a global asymmetric frequency shift of its azimuthal components; where\r\nthe m = 0 and m = ±1 components of the ℓ = 1 dipole mode will be shifted by two\r\ndifferent power laws, respectively. And the other being a reduced visibility of dipole mixed\r\nmode amplitudes in the power spectra, where stars presenting with this feature are denoted as\r\nsuppressed.\r\nSeveral studies of the suppressed dipole mixed mode amplitudes have been carried out, but thus\r\nfar, no dedicated studies of the asymmetric frequency shifts of suppressed red giants have been\r\nconducted; one reason being that the asymmetric frequency shifts cannot be characterized\r\nwhen the dipole mixed mode amplitudes are severely reduced in many of the suppressed stars.\r\nSincefullysuppressedstarsdonothavedetectablemixed-modestoevaluate, partiallysuppressed\r\nstars, that is, red giant stars presenting with suppressed dipole mixed modes in select parts of\r\ntheir power spectra rather than across the entire spectra, will be the subject of this study as\r\nthe respective mode amplitudes are still visible at high frequencies.\r\nAs such, this study will search for asymmetric frequency shifts on the dipole mixed\r\nmodes of partially suppressed red giant stars; the aim here is to investigate if both\r\nmode suppression and magnetic shifting of dipole mixed modes occur simultaneously.\r\nThisstudywillbeconductedbycreatingapipelinetoestimatepriorsofasteroseismicparameters,\r\nuse the priors to model the power spectra with the stellar modeling code sloscillations_ISTA,\r\nand perform a Bayesian fit of the parameters with the simulated data on the star KIC 6975038,\r\na target with partially suppressed dipolar mode amplitudes identified in the literature, to fit its\r\nmagnetic parameters. I present a novel method to model the stellar power spectra of\r\npartially suppressed red giants by application of a sigmoid profile to the ℓ= 1 dipolar\r\nmode component of the spectra. With the results of this study I aim at constraining\r\nthe cause of this partial dipole mode amplitude suppression, allowing for more detailed\r\nstudies regarding their astrophysical nature. Furthermore, the long term hope for the method\r\nused in this study will be to expand the sample of partially suppressed red giants and fit their\r\nasteroseismic parameters accordingly.","lang":"eng"}],"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","author":[{"first_name":"Kanah","id":"7703505d-3211-11ee-a6a9-a2ab9d936c15","full_name":"Smith, Kanah","last_name":"Smith"}],"publisher":"Institute of Science and Technology Austria","date_created":"2025-06-20T13:27:08Z","keyword":["asteroseismology","stellar physics","red giant","magnetism","suppressed"],"OA_place":"repository","date_updated":"2025-11-07T13:44:16Z","title":"Exploring internal magnetism in partially suppressed red giant stars","degree_awarded":"MS","doi":"10.15479/AT-ISTA-19853","month":"10","oa":1,"language":[{"iso":"eng"}],"file":[{"content_type":"application/zip","checksum":"80d241d11b69af771c1fab0998be4f19","date_updated":"2025-10-08T09:45:33Z","relation":"source_file","date_created":"2025-10-08T08:01:42Z","file_size":8263624,"creator":"ksmith","access_level":"closed","file_id":"20434","file_name":"2025_Smith_Kanah_Thesis.zip"},{"file_name":"2025_Smith_Kanah_Thesis.pdf","file_id":"20439","creator":"ksmith","access_level":"open_access","file_size":9748339,"date_created":"2025-10-09T14:38:57Z","success":1,"relation":"main_file","date_updated":"2025-10-09T14:38:57Z","checksum":"13cb48cc98e00fdfe32f3ff66f17aa26","content_type":"application/pdf"}],"oa_version":"Published Version","type":"dissertation","article_processing_charge":"No"}