NASA’s Hubble Space Telescope has found evidence of a unique weather system on a “hot Jupiter” exoplanet. The space telescope found chromium hydride in the atmosphere of a planet called WASP-31b.
WASP-31b is a giant gas exoplanet that orbits an F-type star in the Crater constellation and was discovered in 2010. It has a mass of 0.478 Jupiters with a radius of 1.549 times that of Jupiter. It is located 0.04659 AU from its hot star and takes just 3.4 days to complete a full orbit around it (for comparison, Earth is about 1 AU from our sun and takes 365 days to complete a full orbit). And to say that WASP-31b is scorching hot is an understatement as it has a surface temperature of about 2,192 degrees Fahrenheit (1,200 degrees Celsius).
As for the weather system on WASP-31b, researchers from SRON Netherlands Institute for Space Research and the University of Groningen studied pictures taken by the Hubble and found that the planet is tidally locked, meaning that only one side of it faces its star at all times. (Images can be seen here.)
What’s even more interesting is that they found evidence of chromium hydride in the “twilight zone” (between the two sides of the planet) and that it can change between liquid and gas, causing a weather system with rain on the night side and gas on the day side. Michiel Min, who is the SRON Exoplanets program leader and a co-author of the study, explained another possible weather feature, “According to theoretical models, the large temperature difference creates strong winds. We want to confirm that with observations.”
Since weather systems are an important feature when attempting to find life on other exoplanets, the fact that the researchers found this on such a hot and inhospitable world provides with them a better understanding for studying “friendlier planets” in the future.
This is the first time that chromium hydride has been found on a “hot Jupiter” in a way that the temperature and pressure lets it act as a weather system. First author Marrick Braam noted, “We should add that we only found chromium hydride using the Hubble space telescope.”
He went on to say that they didn’t observe it from any ground-based telescopes like the European Southern Observatory’s Very Large Telescope which is located in Chile. They will only be able to definitively confirm the chromium hydride weather system with further data that will be collected by the James Webb Space Telescope (JWST) which is scheduled to be launched in October of this year.
Co-author Floris van der Tak weighed in on this subject by stating, “With JWST we are looking for chromium hydride on ten planets with different temperatures, to better understand how the weather systems on those planets depend on the temperature.”
Their study was published in the journal Astronomy and Astrophysics where it can be read in full.