by Claire Levin for UChicago News
Chicago IL (SPX) Oct 10, 2024
Finding planets that could support life is a critical objective in astronomy, with the presence of an atmosphere being a key factor in determining a planet's habitability. Though scientists have discovered Earth-like exoplanets, none have been confirmed to possess atmospheres.
A new study led by Qiao Xue, a PhD student at the University of Chicago, introduces a simpler and more efficient method to determine if exoplanets have atmospheres. Working with Prof. Jacob Bean's team, the researchers showed how the method could identify atmospheres more effectively than prior techniques. Xue's study could accelerate the search for habitable planets Rby revealing patterns in atmosphere formation.
"When we look at a large enough data set, as we will this year with the James Webb Space Telescope, we are hoping to find trends to help us understand more about atmosphere formation-and what makes planets habitable," said Xue.
Investigating planetary atmospheres
To assess whether a planet has an atmosphere, scientists examine clues like temperature variations as a planet orbits its star. Xue's team used a method, first proposed in 2019, that looks at temperature differences between a planet's hottest side and its theoretical maximum temperature. If the measured temperature is lower than expected, it suggests an atmosphere is redistributing heat.
Past challenges arose from the precision required for these measurements, but the James Webb Space Telescope (JWST) has improved scientists' ability to observe infrared energy from planets, providing more accurate temperature readings.
Xue applied the method to planet GJ1132 b, concluding it lacks an atmosphere. "It is therefore not a suitable candidate for life," she said. The technique is more reliable than previous approaches, which could be affected by star activity or atmospheric clouds. "This other technique... is more challenging because it can be confounded by activity on the star and the presence of clouds," added Bean.
By refining how atmospheres are detected, this method helps streamline the search for habitable planets, making it easier to rule out uninhabitable ones.
"This study was exciting because I finally got a chance to work with rocky planets, which are the dream subject of every exoplanet scientist because they have so much potential for life," Xue commented. "Now I'm so excited to see what comes next."
Contributors to the study included Jacob Bean, Michael Zhang, and Edwin Kite from UChicago, along with collaborators from institutions such as the Harvard and Smithsonian Center for Astrophysics, Cornell University, and Peking University.
Research Report:JWST Thermal Emission of the Terrestrial Exoplanet GJ 1132b
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