The rotation of a star and the revolutions of its planets are not necessarily aligned. This
article reviews the measurement techniques, key findings, and theoretical interpretations …

Ultrahot giant exoplanets receive thousands of times Earth's insolation 1, 2. Their high-
temperature atmospheres (greater than 2,000 kelvin) are ideal laboratories for studying …

Context. Ultra-hot Jupiters are excellent laboratories for the study of exoplanetary
atmospheres. WASP-121b is one of the most studied; many recent analyses of its …

We present the first detection of atomic emission lines from the atmosphere of an exoplanet.
We detect neutral iron lines from the dayside of KELT-9b (T eq∼ 4000 K). We combined …

Ultra-hot Jupiters are emerging as a new class of exoplanets. Studying their chemical
compositions and temperature structures will improve our understanding of their mass loss …

KELT-9 b, the hottest known exoplanet, with T eq~ 4400 K, is the archetype of a new planet
class known as ultra-hot Jupiters. These exoplanets are presumed to have an atmosphere …

Aims. We present a novel method for studying the thermal emission of exoplanets as a
function of orbital phase at very high spectral resolution, and use it to investigate the climate …

Ultra-hot Jupiters are tidally locked with their host stars, dividing their atmospheres into a hot
dayside and a colder nightside. As the planet moves through transit, different regions of the …

Context. The field of exo-atmospheric characterisation is progressing at an extraordinary
pace. Atmospheric observations are now available for tens of exoplanets, mainly hot and …

Context. Because of its proximity to an active K-type star, the hot Jupiter WASP-80b has
been identified as a possible excellent target for detecting and measuring He I absorption in …