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Exoplanets are exposed to strong radiation. But life on them could arise

The planets around the Red Dwarfs are still in the game of life.

Evidence of existence of extraterrestrial life would undoubtedly represent the greatest scientific discoveries of the last decades, if not history. I hope astrobiologists are exploring exoplanets, planets outside the solar system, and orbiting their stars.

Thanks to the immense progress in their search, we have seen the discovery of thousands of new worlds in recent years. It is even more exciting that many of them are in a zone suitable for their planetary system.

Especially in exoplanets scientists see potential near the solar system. Exploratory robotic missions can be sent to them, maybe in the coming decades.

Around the dwarfs

The closest known exoplanets that could accommodate life-favoring conditions circulate around the red dwarfs. It is the most numerous type of star in the universe and has an extremely long life for slow hydrogen burning – much longer than the current age of the universe.

This should make red dwarves ideal for life candidates. But there is one problem. Red dwarfs are pretty "moody". There are often massive eruptions that bombard the surface of the surrounding planets with high radiation doses and particles filled with rain.

Highly ultraviolet (UV) radiation is fatal to life because it damages and damages organic molecules, especially nucleic acids, which are the foundation of inheritance.

Intense x-rays and the supply of charged particles from solar eruptions can in turn destroy the planetary atmosphere and its water supply.

However, a new study by a couple of astronomers at the University of Carl Sagan Cornell University gives reason for optimism and says it is not so bad with the UV rays of red dwarfs and its impact on life.

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Two models

Lisa Kaltenegger and Jack O & Malley-James specialize in modeling ambient conditions of distant worlds, and in the new study they took four potentially habitable exoplanets that are closest to the Sun's system.

The four planned planets are the closest Proxima Centauri b, only 4.2 light years away from the Sun, Ross 128b (11 light years), TRAPPIST-1e and LHS-1140b (both about 40 light years).

Malley-James and Kaltenegger have created models of different atmospheric conditions for the explored exoplanes.

One model is currently simulating the atmospheric conditions of the Earth.

The other reflected a scarce, partially eroded atmosphere, and the third anoxic atmosphere with low oxygen content and no ozone layer, an early Earth-like atmosphere.


After that, these three models representing three different states of atmospheres exposed the red dwarf UV radiation. They found that even planetary models with eroded atmosphere and low oxygen content were not exposed to the radiation the young Earth had to face, even during solar eruptions.

Because of this, intense UV radiation should not be a limiting factor for the existence of life on planets circulating around the red dwarfs. So these planets are still an attractive destination for extraterrestrial life.

The best evidence is that high doses of UV radiation are not an obstacle to development and development of life. Life appeared on Earth very soon, only a few hundred million years after the planet was born. That was long before the oxygen content in the atmosphere grew and ozone depleting ozone was formed.

If strong radiation really prevented life, Earth would not be living organisms today. Therefore, we should not break our rods over the nearest exoplanet neighbors. As the classic said, "Life will find its way."

The research was published by the online astronomical journal Monthly Reports of the Royal Astronomical Society.

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