Days after it completed two years in the vacuum of space, Nasa’s James Webb Space Telescope (JWST) has provided scientists with the most detailed look yet at the atmosphere of an exoplanet.
The world’s most powerful observatory observed the differences between its eternal morning and eternal evening atmosphere.
WASP-39b, a hot gas giant orbiting a star 700 light-years away, was among the first targets analyzed by Webb as it began its regular science operations in 2022.
The observations were designed to help researchers quickly learn how to use the telescope’s advanced instruments and realise its full scientific potential. The results have far exceeded expectations, offering unprecedented insights into the composition and characteristics of this distant world.
WASP-39b, often described as a “hot Saturn” due to its size and proximity to its star, has been the subject of extensive study using previous telescopes. However, Webb’s Near-InfraRed Spectrograph (NIRSpec) has revealed a wealth of new information about the planet’s atmosphere.
The research team, led by scientists from various institutions, observed one transit of WASP-39b on July 10, 2022.
During this event, the planet passed in front of its star, allowing Webb to analyse the starlight filtered through the planet’s atmosphere. This technique, known as transmission spectroscopy, provides crucial data about the atmospheric composition.
Webb’s observations covered an impressive wavelength range, significantly broader than previous studies. This expanded view has allowed scientists to detect and measure various elements and molecules in the planet’s atmosphere with unprecedented precision.
One of the most significant findings is the detection of carbon dioxide in WASP-39b’s atmosphere, a first for any exoplanet.
This discovery provides valuable insights into the planet’s formation history and evolution. Additionally, the data has helped refine estimates of the planet’s atmospheric metallicity, a key indicator of its composition and origin.
The study also showcases Webb’s ability to overcome technical challenges. Despite some saturation in the detector due to the brightness of the host star, the research team developed innovative data reduction techniques to extract high-quality spectra across the entire wavelength range.
This early success with WASP-39b demonstrates Webb’s transformative potential in the field of exoplanet research. As the telescope continues its mission, astronomers anticipate many more groundbreaking discoveries that will reshape our understanding of planetary systems beyond our solar system.
The findings from this study, published in Nature Astronomy, mark a new era in exoplanet science. They not only provide a deeper understanding of WASP-39b but also pave the way for future investigations of potentially habitable worlds.
Shambhu Kumar is a science communicator, making complex scientific topics accessible to all. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
