"Although no sub-Neptunes orbit around our Sun, they are the most common type of exoplanet, or planet outside our solar system, that have been observed in the Milky Way. These compact, gas-rich worlds are often hidden beneath thick hazes, keeping their true nature out of reach—until now. Using the James Webb Space Telescope to examine the hot sub-Neptune TOI-421 b, scientists have begun to probe these planets in detail for the first time.
A key finding prior to Webb was that most sub-Neptune atmospheres had flat or featureless transmission spectra. This means that when scientists observed the spectrum of the planet as it passed in front of its host star, instead of seeing spectral features – the chemical fingerprints that would reveal the composition of the atmosphere – they saw only a flat-line spectrum. Astronomers concluded from all of those flat-line spectra that at least certain sub-Neptunes were probably very highly obscured by either clouds or hazes.
The temperature of TOI-421 b is about 1,340 degrees Fahrenheit, well above the presumed threshold. Without haze or clouds, researchers expected to see a clear atmosphere – and they did!
The lightweight hydrogen atmosphere was the big surprise to theresearchers. “We had recently wrapped our mind around the idea that those first few sub-Neptunes observed by Webb had heavy-molecule atmospheres, so that had become our expectation, and then we found the opposite,” said Kempton. This suggests TOI-421 b may have formed and evolved differently from the cooler sub-Neptunes observed previously.
The findings raise big questions: Q: Did TOI-421 b form differently than the cooler sub-Neptunes we’ve studied before?
Q: Could it represent a whole new class of hot, haze-free sub-Neptunes?
Q: Or are we simply beginning to uncover the incredible diversity of planets beyond our solar system?"
SciTechDaily
A: You are beginning to uncover the DESIGNED incredible diversity of planets beyond our solar system. Through faith we understand that the worlds were framed by the word of God,... Hebrews 11:3
