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Stefan Pelletier

Källén Seminar for Young Astronomers on April 12, 2022

Titanium cold-trapping, numerous metals and ions, and the first ever unambiguous detection of vanadium oxide revealed on an ultra-hot giant exoplanet


Not just hot, but ULTRA-hot Jupiters are a new emerging class of exoplanets that just keep on giving in terms of awesome new scientific results. These giant gas planets have very short orbital periods of a few days at most, causing them to be tidally-locked to their host stars (like the moon around the Earth). This means that the enormous amounts of stellar radiation they receive is absorbed by one permanent dayside, while the opposing hemisphere (the nightside) never sees the light of day. The results is a boiling hot dayside with temperatures that can exceed well over 2500K, contrasting with a much colder nightside. These two extremes clash at a planet’s terminator region, where transit spectroscopy can be used to probe the dichotomy between these opposing, drastically different hemispheres.

The ultra-hot Jupiter WASP-76b took the exoplanet community by storm at the turn of the decade with evidence of iron condensation occurring from its hot dayside to its colder nightside (literally iron raining down). I will present results of follow-up high-resolution transit observations of this fascinating planet and report on the plethora of metals, ions, and molecules we detect, and how the relative abundances we infer for these species compares with what we would predict from our knowledge of chemistry.