Scientists at Florida State University have discovered that a third of the rocky planets orbiting red dwarfs may have optimal orbits for liquid water oceans. This makes them ideal candidates for the search for life.
Red dwarfs are the most common stars in the Galaxy, their mass and size several times smaller than the Sun. In recent years, scientists have found several planets that claim to be the closest counterparts to Earth. However, scientists cannot yet say for sure whether the conditions for the birth of life exist on their surfaces.
Planetary scientists from the U.S. were interested in how often such conditions may exist on the most common planets of the Galaxy orbiting red dwarfs. They determined the shape of orbits for a large number of planets, and performed calculations that showed that about two-thirds of these worlds could not support life as a result of tidal forces.
Meanwhile, the remaining one-third of the red dwarf planets would be dominated by conditions conducive to liquid water on them. About 33% of the earth-like planets orbiting red dwarfs have an elongated orbit long enough for their bowels to heat up to temperatures at which they become analogous to Venus rather than Earth. Liquid water cannot exist on such worlds in principle, which makes them unsuitable for the origin and evolution of life.
The other 33% of planets, whose hemispheres differ by no more than 2.1%, would remain cold enough for liquid water oceans to exist on them. This makes such planets one of the most attractive targets for traces of intelligent and unintelligent life.
Tidal forces, which periodically compress and stretch the rocks of smaller objects as they get closer and farther away from their larger neighbor, can make planets uninhabitable. Guided by this idea, scientists determined how elongated the orbits of the 163 already discovered rocky planets orbiting red dwarfs are, and used this data to assess the suitability of these worlds for liquid water and life.
The chemical composition of the atmospheres of exoplanets also influences the presence of liquid water on their surfaces. So far, scientists cannot say exactly what conditions are necessary for life to originate on other planets. However, the search for life on other planets is one of the main tasks of modern astronomy.
