A new study shows that Earth size planets orbiting with in the red dwarf “habitable zones” more like Venus than Earth.
A star’s “habitable zones” is the distance range around a star where planets can have liquid water on their surface. Now the Earth sits at about the center of sun’s habitable zone. Astronomers have found that about 40% of red dwarfs have approximately Earth size planets orbiting them and that some of these are in the stars habitable zone. This fact has lead to speculation that such planet could have life on them. However a recent study shows that tidal forces would dry out these Earth size planets when they are orbiting a red dwarf making them more like Venus than Earth and just as hostile to life.
This affect results from the fact that red dwarfs are fainter and cooler than the sun, meaning that a planet orbiting within a red dwarf’s “habitable zones” would be much closer to their star than the Earth is to the Sun. This results in such planets having a very strong tidal force with the star. This means that any Earth size planet not in a perfectly circular orbit would get stretched and squeezed as this pull changes during the planets orbit. Furthermore this tidal stretching and squeezing heats the planet up such that a planet with liquid water orbiting a star whose mass is less than 1/3 that of the sun would get so hot that its water would evaporate. Light from the star would then split the water vapor into hydrogen and oxygen. This Hydrogen would eventually escape into space while the oxygen combined with carbon to form carbon dioxide thus producing a Venus like planet
As a result the so called Earth like planets orbiting red dwarf stars are hardly Earth like but more like Venus and just as hostile to life. This finding helps show just how unique our solar system and the Earth are.