James Webb Space Telescope finds water in the air of exotic 'sub-Neptune' exoplanet

NASA's James Webb Space Telescope (JWST) has made a groundbreaking discovery, detecting water vapor in the atmosphere of a distant exoplanet known as TOI-421 b. This exoplanet, classified as a "sub-Neptune," orbits a star approximately 244 light-years from Earth and boasts a scorching hot atmosphere.

*Key Findings:*

- "Water Vapor Detection": JWST found evidence of carbon monoxide and sulfur dioxide as well as water vapor in the atmosphere of TOI-421 b. - *Atmospheric Composition*: The data suggests that the atmosphere contains a significant amount of hydrogen, with no evidence of methane or carbon dioxide.

- *Challenging Existing Theories*: These findings challenge existing theories about the formation and evolution of sub-Neptune planets, particularly regarding their atmospheric composition and cloud coverage ¹.

*The Exoplanet TOI-421 b:*

- *Sub-Neptune Classification*: TOI-421 b is a type of exoplanet that is larger than Earth but smaller than Neptune, with a mass similar to Saturn's.

- *Temperature of the Atmosphere*: The extremely hot atmosphere of the exoplanet may have an effect on whether or not it is habitable. - "Unique Atmospheric Features": The JWST observations showed that, contrary to expectations based on observations of similar planets 2 and 3, TOI-421 b's atmosphere may be less obscured by haze or clouds than previously thought. *Implications and Future Research:*

- "Understanding Sub-Neptunes": This discovery sheds light on the formation and evolution of sub-Neptune planets, which are common in our galaxy but do not exist in our solar system in any other way. - *Future Studies*: Further research using JWST and other telescopes could reveal more about the atmospheric conditions and potential habitability of similar exoplanets ³.

You might like Therefore, the spectra of sub-Neptunes have generally provided little useful information, rather than displaying chemical fingerprints that could indicate the presence of atmospheric molecules like carbon dioxide, methane, or water vapor. Astronomers suggested that clouds or hazes could be obscuring the signals, which would explain the lack of detail. However, the researchers believed that TOI-421 b might be unique and provide a unique opportunity. “Why did we look at TOI-421 b, this planet? Principal investigator Eliza Kempton, an astronomy professor at the University of Maryland, stated in a statement, "We thought that maybe it wouldn't have hazes." "And the reason is that there were some earlier data that suggested that maybe [sub-Neptune] planets over a certain temperature range were less obscured by haze or clouds than others," the authors write. the most recent information on rocket launches, skywatching events, and other space news! Previous observations with NASA’s Hubble Space Telescope had shown that flat spectral features are common among sub-Neptunes with temperatures below about 1,070 degrees Fahrenheit (577 degrees Celsius).
The researchers wrote in the new study that "Sub-Neptunes hotter than this threshold are also expected to be haze free" because "methane, and thus the hydrocarbon precursors to haze formation, should be less abundant as carbon monoxide becomes the predominant carbon-bearing molecule." The team was rewarded with a rich atmospheric profile after observing two transits with the JWST's Near Infrared Spectrograph, Near Infrared Imager, and Slitless Spectrograph instruments. With an estimated atmospheric temperature of 1,340 degrees Fahrenheit (727 degrees C), TOI-421 b falls into this potentially haze-free category. Brian Davenport, a Ph.D. student at the University of Maryland who carried out the primary data analysis, stated in the same statement, "We saw spectral features that we attribute to various gases, and that allowed us to determine the composition of the atmosphere." The team found evidence of carbon monoxide and sulfur dioxide as well as water vapor in the atmosphere of TOI-421 b. Notably, they did not find evidence of methane or carbon dioxide. Additionally, the data suggest that there is a significant amount of hydrogen in the atmosphere. The existing theories regarding the formation and evolution of sub-Neptune planets are put to the test by some of these surprising findings. Kempton stated, "We had recently wrapped our mind around the idea that those first few sub-Neptunes observed by Webb had atmospheres of heavy molecules, so that had become our expectation." However, Kempton and his colleagues discovered the opposite. This suggests that the formation and evolution of TOI-421 b may have been distinct from those of cooler sub-Neptunes like TOI-270 d, which were previously observed. Because it closely resembles the host star of TOI-421 b, the hydrogen-rich atmosphere is particularly intriguing. Kempton stated, "You would get the same combination of gases if you just took the same gas that made the host star, plopped it on top of a planet's atmosphere, and put it at the much cooler temperature of this planet." "That process is different from other sub-Neptunes that have been observed with Webb so far, and it is more in line with the giant planets in our solar system." She went on to say, "I had been waiting for Webb my entire career so that we could meaningfully characterize the atmospheres of these smaller planets." "We're getting a better understanding of how sub-Neptunes formed and evolved by studying their atmospheres, and one part of that is understanding why they don't exist in our solar system."