New Study by NASA’s Kepler Space Telescope Reveals Exoplanets Losing Atmospheres
A groundbreaking study utilizing NASA’s retired Kepler Space Telescope has provided compelling evidence suggesting that certain exoplanets are experiencing the loss of their atmospheres and subsequently shrinking in size. This fascinating discovery may hold the key to explaining the “size gap” observed in exoplanets ranging from 1.5 to 2 times the size of Earth.
The researchers propose that sub-Neptunes, if lacking sufficient mass to retain their atmospheres, may shrink to the size of super-Earths. Two potential mechanisms have been put forth to explain this atmospheric loss phenomenon: core-powered mass loss and photoevaporation.
Core-powered mass loss occurs when the radiation emitted by a planet’s hot core expels its atmosphere, while photoevaporation takes place when a planet’s atmosphere is blown away by the radiation emitted by its host star. In their investigation, the researchers found new evidence supporting the theory of core-powered mass loss.
To conduct their study, the scientists analyzed data from NASA’s K2 mission, focusing on the Praesepe and Hyades star clusters, aged between 600 million and 800 million years. Surprisingly, it was observed that almost all the stars within these clusters still possess a sub-Neptune planet or planet candidate in their orbits. This indicates that photoevaporation is not likely responsible for the atmospheric loss in these systems.
Based on these findings, the researchers thus conclude that core-powered mass loss is the most plausible explanation for the gradual atmospheric loss in less massive sub-Neptunes over time.
However, further research is necessary to validate these findings and gain a more comprehensive understanding of the mechanisms underlying atmospheric loss in exoplanets. NASA’s Kepler Space Telescope, which was instrumental in this study, concluded its mission in 2018 after successfully identifying thousands of confirmed exoplanets.
This noteworthy study was conducted in collaboration with the NASA Exoplanet Archive, operated by Caltech under contract with NASA’s Jet Propulsion Laboratory. The joint effort of these esteemed institutions promises to shed further light on the mysteries of our celestial surroundings.
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