\u201cThese first observational results from an Earth-size, rocky planet open the door to many future possibilities for studying rocky planet atmospheres with Webb,\u201d agreed Mark Clampin, Astrophysics Division director at NASA Headquarters in Washington. \u201cWebb is bringing us closer and closer to a new understanding of Earth-like worlds outside our solar system, and the mission is only just getting started.\u201d<\/p>\n\n\n\n A flat line in a transmission spectrum, like this one, can be exciting \u2013 it can tell us a lot about the planet. Researchers used NASA\u2019s James Webb Space Telescope\u2019s Near-Infrared Spectrograph (NIRSpec) to observe exoplanet LHS 475 b on August 31, 2022. As this spectrum shows, Webb did not observe a detectable quantity of any element or molecule. The data (white dots) are consistent with a featureless spectrum representative of a planet that has no atmosphere (yellow line). The purple line represents a pure carbon dioxide atmosphere and is indistinguishable from a flat line at the current level of precision. The green line represents a pure methane atmosphere, which is not favored since if methane were present, it would be expected to block more starlight at 3.3 microns.Credits: Illustration: NASA, ESA, CSA, L. Hustak (STScI); Science: K. Stevenson, J. Lustig-Yaeger, E. May (Johns Hopkins University Applied Physics Laboratory), G. Fu (Johns Hopkins University), and S. Moran (University of Arizona)Download the full-resolution, uncompressed version and supporting visuals from the Space Telescope Science Institute.<\/a><\/p>\n\n\n\n Among all operating telescopes, only Webb is capable of characterizing the atmospheres of Earth-sized exoplanets. The team attempted to assess what is in the planet\u2019s atmosphere by analyzing its transmission spectrum<\/a>. Although the data shows that this is an Earth-sized terrestrial planet, they do not yet know if it has an atmosphere. \u201cThe observatory\u2019s data are beautiful,\u201d said Erin May, also of the Johns Hopkins University Applied Physics Laboratory. \u201cThe telescope is so sensitive that it can easily detect a range of molecules, but we can\u2019t yet make any definitive conclusions about the planet\u2019s atmosphere.\u201d<\/p>\n\n\n\n Although the team can\u2019t conclude what is present, they can definitely say what is not<\/em> present. \u201cThere are some terrestrial-type atmospheres that we can rule out,\u201d explained Lustig-Yaeger. \u201cIt can\u2019t have a thick methane-dominated atmosphere, similar to that of Saturn\u2019s moon Titan.\u201d<\/p>\n\n\n\n The team also notes that while it\u2019s possible the planet has no atmosphere, there are some atmospheric compositions that have not been ruled out, such as a pure carbon dioxide atmosphere. \u201cCounterintuitively, a 100% carbon dioxide atmosphere is so much more compact that it becomes very challenging to detect,\u201d said Lustig-Yaeger. Even more precise measurements are required for the team to distinguish a pure carbon dioxide atmosphere from no atmosphere at all. The researchers are scheduled to obtain additional spectra with upcoming observations this summer.<\/p>\n\n\n\n Webb also revealed that the planet is a few hundred degrees warmer than Earth, so if clouds are detected, it may lead the researchers to conclude that the planet is more like Venus, which has a carbon dioxide atmosphere and is perpetually shrouded in thick clouds. \u201cWe\u2019re at the forefront of studying small, rocky exoplanets,\u201d Lustig-Yaeger said. \u201cWe have barely begun scratching the surface of what their atmospheres might be like.\u201d<\/p>\n\n\n\n The researchers also confirmed that the planet completes an orbit in just two days, information that was almost instantaneously revealed by Webb\u2019s precise\u00a0light curve. Although LHS 475 b is closer to its star than any planet in our solar system, its\u00a0red dwarf star<\/a>\u00a0is less than half the temperature of the Sun, so the researchers project it still could have an atmosphere.<\/p>\n\n\n\n How do researchers spot a distant planet? By observing the changes in light as it orbits its star. A light curve from NASA\u2019s James Webb Space Telescope\u2019s Near-Infrared Spectrograph (NIRSpec) shows the change in brightness from the LHS 475 star system over time as the planet transited the star on August 31, 2022. LHS 475 b is a rocky, Earth-sized exoplanet that orbits a red dwarf star roughly 41 light-years away, in the constellation Octans. The planet is extremely close to its star, completing one orbit in two Earth-days. The planet\u2019s confirmation was made possible by Webb\u2019s data.Credits: Illustration: NASA, ESA, CSA, L. Hustak (STScI); Science: K. Stevenson, J. Lustig-Yaeger, E. May (Johns Hopkins University Applied Physics Laboratory), G. Fu (Johns Hopkins University), and S. Moran (University of Arizona)Download the full-resolution, uncompressed version and supporting visuals from the Space Telescope Science Institute.<\/a><\/p>\n\n\n\n The researchers\u2019 findings have opened the possibilities of pinpointing Earth-sized planets orbiting smaller red dwarf stars. \u201cThis rocky planet confirmation highlights the precision of the mission\u2019s instruments,\u201d Stevenson said. \u201cAnd it is only the first of many discoveries that it will make.\u201d Lustig-Yaeger agreed. \u201cWith this telescope, rocky exoplanets are the new frontier.\u201d<\/p>\n\n\n\n LHS 475 b is relatively close, at only 41 light-years away, in the constellation Octans.<\/p>\n\n\n\n The team\u2019s results were presented at a press conference of the American Astronomical Society (AAS) on Wednesday, Jan. 11, 2023.<\/p>\n\n\n\n We recommend you: NASA\u2019s Webb Telescope Reveals Links Between Galaxies Near and Far<\/a><\/p>\n\n\n\n![\"Graphic](\"https:\/\/www.nasa.gov\/sites\/default\/files\/styles\/full_width\/public\/thumbnails\/image\/stsci-01gnvwz3ckz9dt4ev4n2tpmrph.png?itok=b1jt3LYw\" "\\"\\"\/")
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