Recent observations of the exoplanet named WASP-107b reveal an exotic world much stranger than researchers may have realized when it was first discovered in 2017.
A giant gas planet located 200 million lightyears away had already caught the attention of astronomers long intrigued by its light and “fluffy” composition not unlike cotton candy. But recent observations of the exoplanet named WASP-107b reveal an exotic world much stranger than researchers realized.
Using data from NASA’s James Webb Space Telescope, a team of European astronomers were able to draw some conclusions about the atmospheric composition of the Neptune-like gas giant. Not only is the exoplanet scorching hot (with an outer atmosphere that’s more than 900 degrees Fahrenheit), but the researchers found that it’s home to sandy clouds high in the atmosphere that can fall like rain onto its surface.
The findings, published in June in the journal Nature, were announced on Wednesday.
“We are unravelling new worlds,” French astronomer and study co-author Achrène Dyrek said in a statement. “(The Webb telescope) enables a deep atmospheric characterization of an exoplanet that does not have any counterpart in our solar system.”
Why is WASP-107b known as a ‘fluffy’ planet?
Despite being the size of Jupiter, WASP-107b has only 12% of Jupiter’s mass, according to NASA. Though it’s the size of a little more than 30 Earths, the exoplanet orbits a star slightly cooler and less massive than our sun.
First discovered in 2017, WASP-107b has come to be known among astronomers as a “fluffy” planet due to it’s relative lack of density compared to its gigantic size. This composition enabled the European astronomers to look deep into its atmosphere in a way not possible for the dense giant that is Jupiter.
Data from NASA’s state-of-the-art James Webb Space Telescope provided the European researchers with the opportunity to study and unravel the complex chemical composition of the gaseous planet’s atmosphere.
The team discovered the presence of water vapor and sulfur dioxide, a chemical the produces the telltale odor of burnt matches. But what was unusual was that the scientists found no trace of the greenhouse gas methane.
Methane’s absence hints at a potential that the planet has a warm interior, according to the researchers.
The discovery of sulfur dioxide also surprised the team, as previous models of WASP-107b had predicted its absence. However, its presence seems to explain the planet’s “fluffiness,” the researchers explained. Despite its cool-temperature host star emitting a small fraction of high-energy photons, these photons can reach deep into the planet’s atmosphere and create chemical reactions required to produce sulfur dioxide.
Perhaps most intriguing was the team’s discovery of high-altitude silicate sand clouds similar to the very substance we humans find on beaches throughout the world. And just like water droplets on Earth condense and fall from clouds as rain, so to does the silicate vapor, said Michiel Min, an astronomer at the University of Amsterdam and co-author of the study. Observations appear to indicate that the silicate falls like rain toward the planet’s hotter interior and then evaporates back up to again form clouds.
“This is very similar to the water vapor and cloud cycle on our own Earth but with droplets made of sand,” Min said in a statement.
The European astronomers are among many worldwide who are more frequently harnessing NASA’s James Webb Space Telescope to make new discoveries about mysterious star-orbiting exoplanets. Just this September, Webb helped uncover evidence of a possible ocean world larger than Earth with conditions that could support life. And last week, the telescope helped researchers pinpoint the oldest black hole ever discovered.
The team studying WASP-107-b made their observations using the telescope’s Mid-Infrared Instrument (MIRI), which has sensitive detectors that provide the capability to see the red-shifted light of distant galaxies, newly forming stars and faintly visible comets.
“The discovery of clouds of sand, water, and sulfur dioxide on this fluffy exoplanet by (Webb’s) MIRI instrument is a pivotal milestone,” Leen Decin, an astronomer at KU Leuven in Belgium and another study co-author, said in a statement. “It reshapes our understanding of planetary formation and evolution, shedding new light on our own solar system.”