The NASA/ESA/CSA James Webb Space Telescope (JWST) is the largest, most powerful and most complex telescope ever launched into space. Three years into its operations, JWST is revolutionizing our understanding of planets beyond our own solar system by collecting rich datasets on the atmospheres of these far-away worlds.
However, data alone is not enough to understand our universe - it must be interpreted. Models are critical for understanding the physical and chemical processes that give rise to observations. They can also illuminate the state of planetary atmospheres and provide insights into planetary formation, evolution and even, perhaps, habitability.
Together, Lawrence Livermore National Laboratory (LLNL), Arizona State University and Michigan State University will dive deep into uncovering the compositions of 70 exoplanets through LLNL's Computing Grand Challenge Program, which allocates significant quantities of institutional computational resources to LLNL scientists to perform cutting-edge research.
"An endeavor to uniformly model such a large sample of planets - from scorching worlds more massive than Jupiter, to temperate and small Earth-mass planets - has yet to be undertaken," said LLNL principal investigator Peter McGill. "This task can really only be accomplished using LLNL's world-class high performance computing platforms."
The project will focus on running the models to explain transit data gathered by JWST. When an exoplanet transits in front of its star, some of the starlight will pass through the planet's atmosphere. As that happens, molecules in the planet's atmosphere, such as water or carbon dioxide, will absorb some of the light at specific wavelengths. Observing exoplanet transits at different wavelengths can probe these features and uncover the composition of the planet's atmosphere.
Almost 6,000 exoplanets have been discovered to-date, but exactly how they form remains unclear. By observing and modeling planets of different ages, particularly those that are deemed "young", researchers hope to link the composition of atmospheres with planetary formation and evolution theories. This is one of the key goals of the KRONOS program - the largest observational program in JWST's most recent cycle, co-led by Michigan State University's Adina Feinstein and Arizona State University's Luis Welbanks. With over 154 hours of designated JWST time, this collaboration will probe the atmospheres of seven young systems with ages spanning from 20 to 300 million years old.
"Understanding the compositions of planetary atmospheres at different ages is still a big unknown because these planets are hard to find and even harder to characterize within the exoplanet community," said KRONOS program co-principal investigator Adina Feinstein, a NASA Sagan Fellow and incoming assistant professor at MSU. "With the precision and instruments aboard JWST, we're excited to have the ability to begin to directly address questions of what natal planets look like."
The atmospheric models will illuminate the compositions of a diversity of exoplanet atmospheres, which can in turn be used to understand how planets form and evolve and if they harbor conditions favorable for life.
"We are taking some of the first steps to probe young exoplanet atmospheres - a largely unknown population. Through our strategic partnership, we will push the limits of our models and data, looking for new insights into both planetary atmospheres and their host stars," said KRONOS co-principal investigator Luis Welbanks, a 51 Pegasi b fellow and incoming assistant professor at Arizona State University.
Once completed, the atmospheric models developed by the team will be made publicly available to the astronomy community, with the hopes of encouraging open collaborative science and making a lasting impact in the field.
