Scientists observed exoplanet atmosphere in more detail than ever before

A complete study yet of an exoplanet atmosphere. 

illustration of exoplanet
Image Credit: NASA/JPL-Caltech

An international team of scientists including the University of Exeter has used NASA/ESA Hubble Space Telescope to analyze the atmosphere of the hot exoplanet WASP-39b. Through this data, they actually want to create the complete study yet of an exoplanet atmosphere.

The atmospheric composition of WASP-39b suggests that the development procedures of exoplanets can be altogether different from those of our own Solar System giants. Examining it can provide new insight into how and where planets form around a star.

Lead investigator Hannah Wakeford from the University of Exeter in the UK said, “We need to look outward to help us understand our own Solar System.”

Scientists combined the capacities of the NASA/ESA Hubble Space Telescope with those of other ground-and space-based telescopes for a point by point investigation of the exoplanet WASP-39b. They have created an entire range of an exoplanet’s atmosphere conceivable with show day innovation.

WASP-39b is orbiting a Sun-like star, about 700 light-years from Earth. The exoplanet is classified as a “Hot-Saturn”, reflecting both its mass is similar to the planet Saturn in our own Solar System and its proximity to its parent star. This study found that the two planets, despite having a similar mass, are profoundly different in many ways. Not only is WASP-39b not known to have a ring system, it also has a puffy atmosphere that is free of high-altitude clouds. This characteristic allowed Hubble to peer deep into its atmosphere.

By dissecting starlight filtering through the planet’s atmosphere the team found clear evidence for atmospheric water vapor. In fact, WASP-39b has three times as much water as Saturn does. Although the researchers had predicted they would see water vapor, they were surprised by the amount that they found. This surprise, combined with the water abundance allowed to infer the presence of a large amount of heavier elements in the atmosphere. This, in turn, suggests that the planet was bombarded by a lot of icy material which gathered in its atmosphere. This kind of bombardment would only be possible if WASP-39b formed much further away from its host star than it is right now.

Co-author David Sing from the University of Exeter, said, “WASP-39b shows exoplanets are full of surprises and can have very different compositions than those of our Solar System.”

“Hopefully this diversity we see in exoplanets will help us figure out all the different ways a planet can form and evolve.”

Scientists now further planning use the NASA/ESA/CSA James Webb Space Telescope — scheduled to launch in 2019 — to capture an even more complete spectrum of the atmosphere of WASP-39b. Through this, they will able to collect data about the planet’s atmospheric carbon, which absorbs light of longer wavelengths than Hubble can see.