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Examining Correlations Between Planetary and Stellar Properties Using a Bayesian Framework- [electronic resource]

자료유형: 학위논문파일 국외

최종처리일시: 20240214101929

ISBN: 9798380724739

DDC: 530

저자명: Safsten, Emily.

서명/저자: Examining Correlations Between Planetary and Stellar Properties Using a Bayesian Framework - [electronic resource]

발행사항: [S.l.]: : The Pennsylvania State University., 2023

발행사항: Ann Arbor : : ProQuest Dissertations & Theses,, 2023

형태사항: 1 online resource(163 p.)

주기사항: Source: Dissertations Abstracts International, Volume: 85-05, Section: B.

주기사항: Advisor: Dawson, Rebekah.

학위논문주기: Thesis (Ph.D.)--The Pennsylvania State University, 2023.

사용제한주기: This item must not be sold to any third party vendors.

초록/해제: 요약The thousands of exoplanets discovered to date have revealed a variety of worlds and orbital architectures. Observed correlations of planetary properties with other stellar or planetary parameters can offer clues about planets' origins and evolution. However, it can be difficult to distinguish the true underlying cause of an observed trend because stellar parameters are often interrelated. In particular, it is often unknown whether a planetary property is due to the age of the system - meaning it evolves over time - or other parameters that may be related to the age - meaning it is determined by formation conditions. Additionally, small sample sizes and large measurement uncertainties can cast doubt on whether a supposed trend actually exists.To address this problem, we develop a Bayesian statistical framework that uses odds ratios to compare hypotheses for the source of an observed trend of a planetary property. We define three types of hypotheses: Nurture, in which the property is due to the system age; Nature, in which the property is due to some other observed system parameter; and Chance, in which the property is unrelated to any observed parameters. We apply this framework to the proposed age trends of 2:1 orbital resonances, stellar obliquities of hot Jupiter hosts, and eccentricities of hot Jupiters. We find that stellar obliquities of stars with hot Jupiters are most likely driven by stellar temperature, not age. We find that the data very strongly support a trend of hot Jupiter orbital eccentricities due to stellar age over a trend due to semimajor axis. We do not find enough evidence to support that 2:1 orbital resonances are disrupted over time.We next examine the impact on our results of formally incorporating measurement uncertainties. In each case we analyze, while uncertainties do affect the numerical value of the odds ratio, our overall conclusions remain the same. We also use updated samples for the 2:1 resonances and stellar obliquities cases and again find our conclusions unchanged. Through simulated 2:1 resonance data, we show that sample size may be more important than measurement precision for drawing a firm conclusion in this case.Finally, we apply our framework to the small planet radius valley. The most favored theories for the formation of the valley are core-powered mass loss and photoevaporation. We compare these hypotheses using the data from the California-Kepler Survey (CKS) and data from the Gaia-Kepler-TESS-Host Stellar Properties (GKTH) catalog. The results from the CKS data depend on the assumptions regarding core mass and initial atmospheric mass fraction, but strongly favor core-powered mass loss when we follow the respective prescriptions from studies on each process. The GKTH data strongly support core-powered mass loss regardless of these assumptions. We do see a dependence of our results on period and stellar temperature, which we will investigate further in the future.