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James Webb researcher on how telescope will investigate exoplanet atmospheres

When the James Webb Space Telescope begins science operations this summer, it will be used to investigate a wide variety of astronomical objects, from supermassive black holes to distant galaxies. One of Webb’s big scientific goals is to learn more about exoplanets, or planets outside our solar system, and in particular to look at exoplanet atmospheres. It is extremely difficult to tell whether an exoplanet has an atmosphere or what that atmosphere might be composed of using current telescopes, but Webb’s sensitive instruments will be able to detect these atmospheres and learn more about distant planets — potentially even finding habitable worlds.

One of the researchers who will be using Webb to analyze exoplanet atmospheres, Knicole Colón, Webb’s deputy project scientist for exoplanet science, has shared more about this work in a recent NASA blog post:

“One specific exoplanet observation that will be done with Webb involves collecting observations over the course of a planet’s orbit to enable measurements of the atmospheric composition and dynamics,” Colón writes. “I am involved in a program to observe the gas giant HD 80606 b as part of Webb’s first year of observations. Because the orbit of HD 80606 b is extremely eccentric (non-circular) and long (111 days), the amount of energy received by the planet from its star ranges from approximately 1 to 950 times what Earth receives from the Sun! This results in extreme temperature variations, which are predicted to cause clouds to rapidly form and dissipate in the planet’s atmosphere on very short timescales.”

To learn more about these dramatic atmospheric variations, Colón’s team will use Webb’s Near InfraRed Spectrograph or NIRSpec instrument to analyze light coming from the planet to learn about its composition: “Our science team will probe these predicted cloud dynamics in real-time over the course of a continuous ~18 hour observation of HD 80606 b as it passes behind its star, using the NIRSpec instrument on Webb to measure thermal light from the planet’s atmosphere.”

As well as gas giants like HD 80606 b, in its first cycle of research Webb will also look at the atmospheres of Earth-like or terrestrial planets, examine hot rocky exoplanets covered in volcanoes, investigate the disks of matter from which planets form, and look at extreme worlds close to their host stars called hot Jupiters.

This builds on work done by current exoplanet-hunting telescopes like the Transiting Exoplanet Survey Satellite, or TESS, Colón writes: “With TESS and other surveys continuing to discover additional planets in our galaxy at a regular pace and Webb preparing to study the atmospheres of many of these newly discovered worlds, our exoplanet adventures are in many ways just beginning.”

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