The Space Photometry Revolution: Precise Star and Planet Properties in the Kepler, K2 & TESS Era

dc.contributor.advisor Huber, Daniel
dc.contributor.author Chontos, Ashley
dc.contributor.department Astronomy
dc.date.accessioned 2022-10-19T22:36:28Z
dc.date.available 2022-10-19T22:36:28Z
dc.date.issued 2022
dc.description.degree Ph.D.
dc.identifier.uri https://hdl.handle.net/10125/103948
dc.subject Astronomy
dc.subject Astrophysics
dc.title The Space Photometry Revolution: Precise Star and Planet Properties in the Kepler, K2 & TESS Era
dc.type Thesis
dcterms.abstract The field of exoplanetary science recently surpassed a milestone by confirming more than five thousand planets beyond the solar system. However, more than 99% of known exoplanets are indirectly detected and therefore, the derived planet properties critically depend on fundamental stellar properties. The main theme of this thesis is to use the tools of stellar astrophysics to precisely characterize planetary systems. One powerful tool to measure precise stellar properties is asteroseismology, the study of stellar oscillations which provides masses, radii and ages of host stars with exquisite precision and accuracy. An open-source asteroseismology pipeline was developed from well-tested closed-source tools, benchmarked to the asteroseismic legacy sample to ensure reproducible Kepler mission results, and then publicly released for the broader astronomy community to analyze forthcoming TESS data. The pipeline successfully identified solar-like oscillations in benchmark systems like the solar analog alpha Men A as well as KOI 4, the first new planet host identified by the Kepler mission. KOI 4 remained unconfirmed for nearly a decade, the planet discovery which hinged on the recharacterization of the host star using asteroseismology. The asteroseismic constraints placed the star in a rare parameter space as a subgiant host, where planets are expected to undergo quick inward migration and engulfment by their host star. The lack of orbital period decay via star-planet tidal interactions in the KOI 4 system enabled the first observational constraint on the tidal quality factor in an evolved system. Even for non-oscillating subgiants though, the rapid phase in stellar evolution uniquely constrains system masses and ages, thus providing an ideal sample to test evolution theories for post-main-sequence systems. A homogeneous sample of subgiant planetary systems is presented as part of the TESS-Keck Survey (TKS), a complementary ground-based spectroscopic survey to follow up, confirm and characterize transiting TESS planets. Precise planet densities, system ages and long-term orbital properties are presented for 22 TESS subgiant systems, providing a first look into the differences between main-sequence and evolved planet distributions. Preliminary results suggest an increased efficiency of tidal interactions in evolved systems through the dearth of larger, more massive planets, which is consistent with predictions from tidal theories. In addition, more than half of the systems show strong evidence for planet multiplicity, which was previously thought to be uncommon around such stars. Further analysis of the planet sample can be used to place quantitative constraints on processes related to tidal dissipation like orbital period decay and circularization.
dcterms.extent 255 pages
dcterms.language en
dcterms.publisher University of Hawai'i at Manoa
dcterms.rights All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dcterms.type Text
local.identifier.alturi http://dissertations.umi.com/hawii:11529
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