Title: Climbing the Compositional Ladder of Gas Dwarfs, Brown Dwarfs and Stars
Speaker: Caprice Phillips (OSU)
Abstract:
Understanding the diversity of planetary and substellar atmospheres is essential to advancing the search for life beyond Earth and unraveling the processes that govern planet formation. In this talk, theoretical models and observational data are employed to traverse the compositional ladder, with the goal of detecting potential biosignatures, identifying planetary formation tracers, and ultimately characterizing the atmospheres of gas dwarfs, brown dwarfs, and solar-type stars. Specifically, on the first rung of the compositional ladder, I will discuss a metric of detection and detectability of a potential biosignature ammonia (NH3) in nearby gas dwarfs and the closest transiting exoplanet with both JWST and the Twinkle space mission. I will discuss the sensitivity to NH3 detection to atmospheric composition, the concentration of NH3 and the presence of clouds. As we ascend the compositional ladder, our focus shifts to brown dwarf analysis through the dual approaches of atmospheric retrievals and forward modeling. I will discuss the complex regime of young cloudy L-type planetary-mass companions. I will show the technical guidance on retrieving young, cloudy L dwarf atmospheres and illustrates how current retrieval frameworks can discriminate between cloudless and cloudy model scenarios. Approaching the top of the compositional ladder, I will turn to high-resolution spectroscopic studies of solar-type stars that serve as hosts to brown dwarf companions. I will show how I uniformly explore stellar parameters for a sample of solar-type hosts of benchmark brown dwarfs and discuss the ongoing survey.
