(ORDO NEWS) — In addition to rocky and gas planets, there are worlds near red dwarfs where solid rocks are densely mixed with water.
The vast majority of stars in our galaxy are red dwarfs , small and dim. Therefore, the question of how the planets look near such luminaries, and whether life is possible on them, is especially important.
To do this, scientists from France and the United States conducted a “census” of known planets orbiting red dwarfs.
After determining their density, astronomers have found that many such worlds can contain huge amounts of moisture – which, however, hardly makes them habitable.
An article by Rafael Luque and Enric Pallé was published in the journal Science . In it, astronomers analyze the masses and radii of 43 planets orbiting the red dwarfs of the Milky Way.
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 very 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 a thousand times less: water makes up only 0.02 percent of the mass of our “blue” planet.
However, one should not think that these water planets are covered with oceans, where life is seething and intelligent squids swim.
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 the forms we are familiar with.
However, such “semi-aquatic” planets are still too poorly understood, and only future research will help to reveal many details of their structure.
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