Buzz
Planets orbiting too close to their host stars risk losing their atmospheres due to intense radiation, forming tails in the process, as revealed by recent astronomical research led by David Ehrenreich from the Geneva Observatory.
The study, featured in Nature, focuses on GJ 436b, a warm, low-mass planet located approximately 10.2 parsecs (33.3 light years) away. Similar in size to Neptune, it is larger than Earth but remains relatively small compared to other cosmic entities.
X-rays emitted by the system’s red dwarf star strip away the planet’s upper atmosphere, while ultraviolet radiation propels the hydrogen atmosphere outward, creating a trailing tail. The planet’s limited mass and weak gravity prevent it from retaining its atmospheric layers.
"Approximately 1000 metric tonnes of hydrogen are being stripped from GJ 436b's atmosphere each second, amounting to just 0.1% of its total mass over a billion years," according to Peter Wheatley, a co-author of the study and astronomer at the University of Warwick in the UK. "This phenomenon is expected to be far more intense on other exoplanets, potentially leading to the complete evaporation or destruction of their atmospheres."
The gas tail trailing GJ 436b stretches an impressive 9 million miles in length and spans about two million miles in width. While this marks the first observed planet with such a tail, it is unlikely to be the only one. Researchers suggest that other hot, rocky exoplanets may have initially resembled the icy gas giant Neptune, only to lose their atmospheres through similar processes.
