The current exoplanet census contains 5,832 confirmed candidates, with more than 7,500 still awaiting confirmation. Of those that have been confirmed, most have been gas giants ranging from Neptune-like bodies (1992) to those similar to or many times the size and mass of Jupiter and Saturn (1883). Like the gas giants of the Solar System, astronomers generally theorized that these types of planets form in the outer reaches of their star system, where conditions are cold enough for gases like hydrogen and helium and volatile compounds (water, ammonia, methane, etc.) will condense or freeze solid.
However, astronomers have noted that many of the gas giants they’ve observed orbited close to their stars, known as “Hot Jupiters.” This has raised questions about whether or not gas giants and other planets migrate after formation until they find their long-term, stable orbits. In a new study, a team from Arizona State University’s School Of Earth and Space Exploration (ASU-SESE) examined the atmospheric chemistry of several Hot and Ultra-Hot Jupiters. After examining WASP-121b, the team came to the unexpected conclusion that it likely formed close to its star.
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