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From Soot Sprites to Planets: Impacts of Elemental Abundances on Planet Populations

Boley, Kiersten M.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1718635775487703

Abstract Details

2024, Doctor of Philosophy, Ohio State University, Astronomy.
Planet formation is intrinsically linked to the star formation history and evolution of the Milky Way through elemental abundances and galactic locations. The environments in which a planet may form infuences their composition or whether a planet population may form at all. There are key stellar abundances that act as tracers for planet formation (e.g., Fe), constrain rocky planet composition (i.e., Fe, Mg, Si), and volatiles that impact the composition of magmas (i.e., H2O, CO2). Historically, spectroscopically-derived stellar abundances have been difcult to obtain for large stellar samples as they require long observations. However, spectroscopic surveys such as LAMOST (Luo et al. 2015) have been instrumental in obtaining stellar abundances. This dissertation uses stellar abundances to connect theoretical and observational studies of exoplanets. Specifcally, we constrain planet formation observationally using two stellar samples where Fe as a proxy for the available metals in the protoplanetary disk at the time of formation. The study of the frst stellar sample resulted in the frst observational study to search the galactic halo for planets placing the frst constraints on planet formation in the halo. With the second stellar sample, we constrained the occurrence rate of super-Earths (1-∼1.8 R⊕) as a function of metallicity ([Fe/H]). Our study challenged conventional theory that predicts that super-Earths had a weaker trend with metallicity with a sample ∼ 2 times larger than previous metal-poor stars, resulting in the frst evidence for a strong trend for super-Earth formation at low-metallicity regime. Considering super-Earth composition post-formation, rocky planets transition through a magma ocean phase where volatiles such as, H2O, CO2 may impact the properties of the magma (i.e., melting temperature, compressibility). To investigate the impact of volatiles on magma ocean planets, we chose to consider the impact of magma composition on the observable properties of lava worlds, planets with long-lived magma oceans. In doing so, we discovered a variety of mantle structures that arise for a given planet mass and surface temperature having implications for long-term volatile storage of rocky planets. Therefore, we developed the framework to determine the water storage capacities of the mantle once a planet has cooled. Specifcally, we considered the amount of water storage of minerals as a function of Mg/Si and found that higher ratios generally lead to minerals with larger water storage capacities. This dissertation demonstrates the importance of elemental abundances on planet populations from planet formation to rocky planet evolution.
Wendy Panero (Advisor)
Ji Wang (Advisor)
151 p.
Astronomy; Astrophysics
planet formation, interior, demographics, water worlds, occurrence rates, small planets, gas giants, metallicity, magma oceans, elemental abundances, exoplanets

Recommended Citations

Citations

  • Boley, K. M. (2024). From Soot Sprites to Planets: Impacts of Elemental Abundances on Planet Populations [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1718635775487703

    APA Style (7th edition)

  • Boley, Kiersten. From Soot Sprites to Planets: Impacts of Elemental Abundances on Planet Populations . 2024. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1718635775487703.

    MLA Style (8th edition)

  • Boley, Kiersten. "From Soot Sprites to Planets: Impacts of Elemental Abundances on Planet Populations ." Doctoral dissertation, Ohio State University, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=osu1718635775487703

    Chicago Manual of Style (17th edition)

osu1718635775487703
© 2024, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.