(ORDO NEWS) — The vast majority of stars in our galaxy are red dwarfs, small and dim. Therefore, the question of how planets look like near such luminaries is especially important, and whether life is possible on them.
Scientists have tested all known discovered planets around such stars and found that many worlds can contain huge amounts of moisture – which, however, hardly makes them inhabited.
Astronomers have analyzed the masses and radii of 43 planets orbiting red dwarfs in the Milky Way galaxy . The work showed that they are divided mainly into three populations, which differ sharply from each other in density and other characteristics.
First, these are compact solid worlds like Earth or Mars; secondly, gas dwarfs, “mini-neptunes”, rich in hydrogen and helium.
The third group consists of planets of a previously unknown type, small and characterized by a rather low density.
This feature can be explained by the high content of water in them – a substance that is quite widespread in space. Scientists estimate that water could account for up to 50 percent of the mass of these planets.
For comparison, on Earth it is thousands of times less: water makes up only 0.02 percent of the mass of our “blue” planet.
Could life exist there?
The fact is that the presence of such a large amount of moisture does not necessarily indicate that the planet is covered with oceans, seas and rivers filled with life, as we are used to seeing on Earth.
Most likely, such worlds form relatively far from their stars, where the main masses of water accumulate, and then migrate to closer orbits.
Here, large amounts of moisture can no longer remain on the surface of the planet without volatilizing.
Therefore, its main mass is preserved at depth, mixed with solid rocks and possibly with molten lava. Such conditions do not fit well with life – at least in forms familiar to us.
However, such “semi-aquatic” planets are still too poorly understood, and only future studies will help reveal many details of their structure.
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