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The artistic design of the planet HD 219134b, one of the rocky exoplanets closest to our solar system. This planet, about 1.6 times larger than the Earth, is extremely hot and has a partially melted surface.
Credit: NASA / JPL-Caltech
Recent studies on exoplanets suggest that there could be thousands of Earth-like worlds in other solar systems, which are only waiting to be discovered. It is unfortunate that their atmospheres – and with them any hope of sustaining life – have probably been erased by their local stars.
Whatever it is, that's what we can remember from a new study published April 19 in the journal Astronomy and Astrophysics. In the new article, a team of European researchers has created a computer model to simulate the formation of atmosphere on Earth-like planets orbiting young and hot stars. Since young suns tend to emit extremely high amounts of x-rays and ultraviolet (UV) radiation, most potentially habitable exoplanets would likely see their atmosphere disappear less than a million years after the birth of the planet. [9 Scientific Excused For Why We Haven’t Found Aliens Yet]
"An Earth-like atmosphere can not form when the planet orbits around the habitable zone of a very active star," the researchers wrote. "Instead, such an atmosphere can only form after the activity of the star has decreased to a much lower level."
When astronomers talk about the activity of a star, they refer to the amount of radiation emitted. Unlike humans and puppies, young stars tend to be very active, and then significantly decrease their activity level as they age. The precise activity levels at different ages depend on the mass of the star.
In the case of the M-dwarf stars, slightly smaller than the Earth's sun and considered the dominant type of stars in nearby solar systems, it sometimes takes several billion years for the Solar activity reaches levels comparable to those of the Earth's sun today. The researchers then discovered that any exoplanet in orbit around this star would be so bombarded by such radiation that there would be little chance that an atmosphere would survive the first 100,000 years.
As a result, the researchers concluded that most of the Earth-like exoplanets detected around dwarf stars in nearby solar systems probably had a very thin, if any, atmosphere, leaving the surfaces of these planets exposed to the damaging effects of solar radiation. . Unfortunately, this means that even on the most livable planets, life might be rarer than expected.
Originally published on Science live.
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