Temperature forecast for WASP-121 b

This video shows the temperature forecast spanning 130 exoplanet-days, across sunrise, noon, sunset and midnight, for the exoplanet WASP-121 b, also known as Tylos.The brighter yellow regions depict areas on the day side of the exoplanet where the temperature soars well above 2000 Kelvins because of its close proximity to its host star, roughly 2.6% of the distance between Earth and the Sun. Owing to the extreme temperature difference between the day and night sides, astronomers suspect evaporated iron and other heavy metals escaping into the higher layers of atmosphere on the day side partially fall back onto lower layers, making it rain iron on the night side. Some of the heavy metals also escape the planet's gravity from the upper atmosphere.

It only takes WASP-121 b roughly 30 hours to complete an orbit around its star.

An international team of astronomers assembled and reprocessed Hubble observations of the exoplanet made in the years 2016, 2018 and 2019. This provided them with a unique dataset that allowed them not only to analyse the atmosphere of WASP-121 b, but also to compare the state of the exoplanet’s atmosphere across several years. They found clear evidence that the observations of WASP-121 b were varying in time. The team then used sophisticated modelling techniques to demonstrate that these temporal variations could be explained by weather patterns in the exoplanet's atmosphere, as seen here.