Nuka-Nepta
New research suggests that astronomers may have been completely wrong about a class of exoplanets they call “mini-Neptunes.”
These worlds, thought to be smaller versions, just 2.4 Earth radii, of gas giants like Neptune, may actually be rocky exoplanets covered by thick, deeply irradiated oceans, according to research by scientists at the Astrophysics Laboratory. from Marseille. . The study, published last month in The letters of the astrophysical journal, threatens to break down the barriers between two classes of exoplanets that astronomers thought were completely separate.
Totally radical
Studying exoplanets tends to involve a bit of deception. Researchers use various imaging techniques to discover things like the density of a world, the chemical composition, and whether it has an atmosphere. In the case of mini-Neptunes, most had assumed that their low density and mass meant that they were covered in a thick, gaseous atmosphere.
Instead, according to the study, some may have oceans of highly pressurized and heated supercritical fluid that has been irradiated by a powerful greenhouse effect. The ocean, like the atmosphere of a gas giant, could explain the low density and mass of exoplanets.
Building bridges
A separate study published in Astronomy and astrophysics They discovered that the same irradiated oceans could also exist on slightly smaller “super-terrestrial” rocky exoplanets, since their environments are capable of having the same powerful greenhouse effect as mini-Neptunes.
Many of their calculations still need to be tested and verified through further exoplanet observations. But if it is maintained, the results suggest that the different worlds could be much more similar than we thought.
READ MORE: Could mini-Neptunes be irradiated ocean planets? [CNRS]
More about exoplanets: Astronomers discover an “intriguing” exoplanet extremely similar to Earth
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