Our understanding of how exoplanets form and evolve relies on analyses of both the mineralogy of protoplanetary disks and their detailed structures; however, these key complementary aspects of disks are usually studied separately. We present initial results from a hybrid model that combines the empirical characterization of the mineralogy of a disk, as determined from its mid-infrared spectral features, with the well-tested MCFOST radiative transfer disk model that takes into account realistic disk density and temperature structures, a combination we call the EaRTH Disk Model. With the results of the mineralogy detection serving as input to the radiative transfer model, we generate mid-infrared spectral energy distributions that reflect both the mineralogical and structural parameters of the corresponding disk. Initial fits of the SED output by the resulting integrated model to Spitzer Space Telescope mid-infrared (IRS) spectra of the protoplanetary disk orbiting the nearby T Tauri star MP Mus demonstrates the potential advantages of this approach by revealing details like the dominance of warm small olivine and cool small pyroxene in the dusty disk of MP Mus. The methodology proposed here provides insight into disk composition and structure, but requires fine-tuning in the radiative transfer stage to reproduce specific spectral features. However, it should be directly applicable to the interpretation of mid-infrared spectra of protoplanetary disks that will be produced by the James Webb Space Telescope. Additionally, while the model can successfully match known observations assuming a typical fiducial protoplanetary disk, it is necessary to alter the model to match data when structural differences are observed, such as a gap or rings; adjusting the model to match infrared observations while remaining consistent with millimeter observations demonstrates the model’s adaptability to different disk structures, which we do using the Spitzer IRS spectra and Atacama Large Millimeter/sub-Millimeter Array (ALMA) observations of MP Mus, as well as the transition disks of GM Aur and LkCa 15. The results illustrate the large differences that occur in protoplanetary disk development despite similar ages, likely the result of planetary formation.
Imaging Science (Ph.D.)
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Grimble, William Allen Richard, "The EaRTH Disk Model: Analysis and Integration of Protoplanetary Disk Mineralogy and Structure" (2022). Thesis. Rochester Institute of Technology. Accessed from
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