Ultra-hot Jupiters offer the opportunity to learn about the chemistry, thermal structure and dynamics in atmospheres at high temperatures. Thanks to high-resolution spectroscopy, we are able to detect metals routinely, and have thus been able to compile an inventory of the composition of the atmospheres of some ultra-hot Jupiters. 

With their short orbital periods, high equilibrium temperatures that simplify the underlying chemistry, and tidal locking that causes extreme temperature and chemical fluctuations between the permanently irradiated hot dayside and the cooler permanently dark nightside, they offer the opportunity to learn not only about the chemical composition, but also about the thermal structure and dynamics in their atmospheres. 

Interpreting the detection of metals in transmission spectra of ultra-hot Jupiters from cross-correlation maps raises some questions: 
What does it mean if the absorption spectrum is Doppler-shifted? What are super-rotational winds, and how do we see them? What does it mean that some species show Doppler shifts and others do not? How do we interpret the presence or absence of certain species? 

During my talk, I will use the analysis of a transmission spectrum of an ultra-hot Jupiter as an example to answer the above questions, and explain what these effects can tell us about the chemical and dynamical properties of the atmosphere.