Caltech/IPAC Lunch Seminar

Unlike in the Solar System's giant planets, refractory elements like Fe, Mg, and Si participate in a variety of interesting atmospheric phenomena in irradiated exoplanets and self-luminous brown dwarfs. I will describe our current understanding of the behavior of these refractory elements through new HST and JWST observations of hot Jupiters and cloudy brown dwarfs. We explore what happens when these refractory elements are condensed by presenting new JWST spectra of two cloudy brown dwarfs, measuring cloud particle composition, crystallinity, particle size, and vertical distribution to unprecedented precision. In particular, these spectra indicate silica grains rather than the expected magnesium-silicates, hinting at the importance of primordial abundances or microphysical details. I will then describe new observations exploring the evaporation of refractory material in hot and ultra-hot Jupiter atmospheres, allowing us to pinpoint the conditions for cloud formation and enabling new constraints on planet formation and migration through refractory-to-volatile abundance ratios. Combined, these results show the wealth of information revealed by studying the behavior of heavy elements in substellar atmospheres with the power of HST and JWST.