Degree

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

Document Type

Dissertation

Abstract

There exists a vastly diverse compilation of exoplanetary systems; ranging from planets the size of Earth to planets larger than Jupiter, planets with or without an atmosphere, planets with rocky compositions to planets with gaseous compositions, and more. Enough planets have been discovered and confirmed to enable statistically reliable statements about demographics, formation mechanisms, planetary properties, etc., all of which require reliable exoplanet parameters. Properly characterizing and understanding these worlds first requires accurate measurements of their host star fundamental properties as exoplanets were, at some point in time, under the direct influence of their host stars. Direct measurements of stars allow for a model-independent opportunity to provide key stellar parameters, namely the radius, effective temperature, and luminosity. One such direct measurement technique is the use of very high angular resolution measurements with long baseline optical interferometry.  Interferometric measurements produce precise, directly measured angular diameters of stars, that are used to calculate model-independent values of the key fundamental stellar parameters. These key fundamental stellar parameters are then used to constrain the corresponding exoplanet parameters.

I use the CHARA Array to directly measure precise angular diameters of three exoplanet host stars, 51 Eri, HD 219134, and HD 158259 and calculate their physical radii, effective temperatures, and luminosities. I then perform exoplanet characterizations using a variety of methods: EXOFASTv2, modeling using Gaussian Processes, and through iso-mass models. In addition, I present RADPy, an open source Python package designed to fit multi-wavelength interferometric data to provide robust determinations of both uniform-disk angular diameters and limb-darkened disk angular diameters. Alongside angular diameter fitting, RADPy also performs spectral energy distribution fits to measure bolometric fluxes. This work presents detailed characterizations of three exoplanet host stars, adding to the growing list of exoplanet hosts that have been observed with long baseline optical interferometry.

Date

7-17-2026

Committee Chair

Boyajian, Tabetha

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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