The most common stars in the universe are smaller and cooler than our Sun, but they can be a lot more violent when it comes to activities and intense ultraviolet radiation. Many rocky worlds have been found around these M-dwarf stars, but their temperamental behavior had researchers question their suitability for life. A new study argues that it is possible for these worlds to actually keep an atmosphere (if they follow a certain evolution).
The team behind the study modeled planets from their molten origin to the formation of a rocky crust and an atmosphere. The simulations showed the first atmosphere to form is likely destroyed by the star – but a second atmosphere could form, and the planets might be able to hold onto that one.
"One of the most intriguing questions right now in exoplanet astronomy is: Can rocky planets orbiting M-dwarf stars maintain atmospheres that could support life?" lead author assistant professor Joshua Krissansen-Totton, from the University of Washinton, said in a statement. "Our findings give reason to expect that some of these planets do have atmospheres, which significantly enhances the chances that these common planetary systems could support life."
The idea is that, as long as the planets are in the habitable zone and not too close to the star, they should be able to form water in their atmosphere quickly enough. At first, the molten planet would be shrouded in hydrogen and this would be blown away by the star – but in planets with a moderate temperature, hydrogen would combine with oxygen to form water.
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