Viable water exoplanets

Viable water exoplanets

Artistic vision of the supposed water world. This is a terrestrial exoplanet, completely covered with water, represented by the example of the Kepler-35A and B double star system

Today, there are about 50 known exoplanets, which cover the diameter from Mars to several Earths and are located in the habitable zone (the temperature is ideal for the presence of liquid water). These worlds are the best candidates for the search for life.

If the exoplanet in the habitable zone removes 10% of the total mass to the water or it lacks an atmosphere with hydrogen or gaseous helium, then such a world is called aquatic. Some scientists believe that the water worlds are unfit for life. They lack sushi, which leads the carbonate-silicate cycle. In this process, carbon dioxide balances between the atmosphere and the inner space of the planet. The researchers decided to re-analyze the physical and geological mechanisms in the aquatic worlds. It turns out that when the pressure of atmospheric carbon dioxide is high enough, sea ice can be enriched with chemicals other than water and runoff. This balances the gas pressure, about the same as the carbonate-silicate cycle.

For this effect to work, the planet needs to rotate about three times faster than the Earth. Then it turns out to develop a polar ice cap and create a temperature gradient in the ocean, contributing to the maintenance mechanism. In addition, this temperature gradient will support the freeze-thaw cycle, which is necessary for the evolution of life in aquatic worlds. Additional calculations are now being conducted on the new “usable” habitat zone. Usually it falls into the standard settings.

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