A boiling Saturn-like planet 700 light-years from the Sun has become the best-studied planet outside of our solar system. Measurements of the planet’s atmosphere by the James Webb Space Telescope have revealed unprecedented details of its chemistry and even allowed astronomers to test methods for detecting extraterrestrial life.
That exoplanet Orbiting a star in the constellation Virgo, WASP-39b made headlines in late August when the James Webb Space Telescope (Webb or JWST) found carbon dioxide in its atmosphere. It was the very first such recognition and experts hailed the discovery as a major breakthrough. Now, less than three months later, an avalanche of studies based on the large telescope’s observations have revealed the smallest details of WASP-39b’s atmosphere, even allowing astronomers to draw inferences about the exoplanet’s formation history.
“These early observations are a harbinger of more amazing science to come with JWST,” said Laura Kreidberg, director of the Max Planck Institute for Astronomy (MPIA) in Germany, who was involved in the observations, in a expression. “We put the telescope through its paces to test its performance, and it was nearly flawless – even better than we had hoped.”
Astronomers used three of Webb’s four instruments to observe the distant planet: the main instrument NIRCam camera and the two spectroscopes NIRISS and NIRSpecwhich split the light of the observed objects into light spectrathe barcode-like fingerprints that reveal the chemical composition of the observed planets and stars.
Observations showed that WASP-39b is shrouded in thick clouds containing sulfur and silicates. These chemicals interact with the parent star’s light and produce sulfur dioxide in a reaction similar to that which produces ozone earth atmosphere.
WASP-39b and a gas giant about a third the size of the solar systems largest planet, Jupiterand orbits just 4.3 million miles (7 million kilometers) from its parent star, or eight times closer than the distance of the Solar System’s innermost planet mercury from the sun.
The sheer intensity of starlight, which surpasses WASP-39b, makes the planet an ideal laboratory for studying such photochemical reactions, scientists said in the statement.
JWST’s level of detail allowed astronomers to peer into WASP-39b’s past and learn how this hot and scorching world formed. From the ratios of carbon to oxygen, potassium to oxygen and sulfur to hydrogen in the planet’s atmosphere, the researchers concluded that the gas giant planet must have formed from the collisions of several smaller planetesimals. In addition, the much higher amount of oxygen in the thick clouds compared to carbon indicated that WASP-39b formed much farther from its star than it orbits today.
“Data like this changes the game,” Natalia Batalha, a professor of astronomy and astrophysics at the University of California, Santa Cruz, who coordinated the observing program, said in the statement.
The observations even allowed astronomers to test methods that could one day help detect life on other exoplanets. This detection would be based on a similar atmospheric analysis performed on WASP-39b and then compare the results to models of alien planets. For example, if the planet shows more oxygen than these models predict, it could be a sign of life.
However, WASP-39b’s proximity to its parent star makes it an unlikely candidate for extraterrestrial life as the planet’s temperature soars to an unbearable 1,650 degrees Fahrenheit (900 degrees Celsius).