NASA’s James Webb Space Telescope (JWST) continues its torrid summer of scientific discoveries, finding the first clear evidence of carbon dioxide in the atmosphere of an exoplanet. The findings have been accepted for publication in the journal Nature. Extrasolar planets, or exoplanets, are any planets outside our solar system. Most of them orbit other stars like Earth orbits the sun, but some free-floating exoplanets (known as rogue planets) orbit a galactic center, unconnected to any other star.
This new discovery means the ground-breaking JWST may be able to detect and measure key molecules like carbon dioxide in the thinner atmospheres of smaller rocky planets in the future. These types of data give scientists insights into the formation, composition and evolution of the galactic planets.
The exoplanet WASP-39b was first discovered in 2011. Seven years later, NASA’s Hubble and Spitzer space telescopes detected water vapor, sodium and potassium in WASP-39b’s atmosphere, providing a glimpse of what is happening around the planet. In 2022, it became the first exoplanet to be studied by JWST.
Orbiting about 700 light-years from Earth, WASP-39b is a hot gas giant with a mass about the same as Saturn, but a diameter about 1.3 times that of Jupiter (our solar system’s largest planet). The planet’s bloat is partly due to the fact that it is about 1,600 degrees Fahrenheit (900 degrees Celsius), giving it the nickname “Hot Saturn.” WASP-39b is in infinite summer because it orbits very close to its star, unlike the cooler, more compact gas giants in our solar system. It’s so close that it completes a full orbit of its star, or a “year,” in just over four Earth days.
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WASP-39b was first reported using ground-based detections of the periodic dimming of light from its host star. This is when the light from the planet’s host star dims as the planet passes in front of it, as during an eclipse. The transit, or this eclipse-like event, could provide researchers with ideal opportunities to probe planetary atmospheres.
Different gases absorb different combinations of colors, meaning researchers “can analyze small changes in the brightness of transmitted light across a spectrum of wavelengths to determine exactly what an atmosphere is made of,” according to NASA. The combination of WASP-39b’s puffy atmosphere and frequent flybys make it a perfect target for a technique called transmission spectroscopy.
Credits: Illustration: NASA, ESA, CSA and L. Hustak (STScI); Science: JWST Transiting Exoplanet Community Science Team for early launch
The team used JWST’s Near Infrared Spectrograph (NIRSpec) for these observations. “As soon as the data appeared on my screen, the large carbon dioxide feature grabbed me,” said Zafar Rustamkulov, a graduate student at Johns Hopkins University and member of the JWST Transiting Exoplanet Community Early Release Science team, of who undertook this investigation. a statement. “It was a special moment, crossing an important threshold in exoplanetary science.”
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Measuring such a subtle difference in the brightness of so many single colors in the 3- to 5.5-micron range in an exoplanet’s transmission spectrum is a first for researchers, NASA reports. It is critical to access this part of the spectrum when measuring the amount of gas, water, methane, and carbon dioxide in exoplanets.
“The detection of such a clear carbon dioxide signal in WASP-39 b bodes well for the detection of atmospheres on smaller Earth-sized planets,” team leader Natalie Batalha of NASA said in a statement. University of California at Santa Cruz.
For scientists, understanding what makes up a planet’s atmosphere is important because it provides a window into its origin and evolution. “Carbon dioxide molecules are sensitive tracers of the planet’s formation history,” research team member Mike Line of Arizona State University said in the NASA statement. “By measuring this feature of carbon dioxide, we can determine how much solid versus gaseous material was used to form this giant gas planet. Over the next decade, JWST will make this measurement for a variety of planets, providing insight into the details of how planets form and the uniqueness of our solar system.