Artist’s impression of the molten surface of a young planet reacting with its atmosphere to form water vapor. Credit: Tadahiro Kimura
A day at the beach for life on other planets.
According to new simulations, fully Earth-like exoplanets with oceans and continents, as well as beaches along their boundaries, may be significantly more common around red dwarfs than previously thought. This indicates that by the end of the decade, current and future
On Earth, both the oceans and continents play critical roles in the geochemical carbon cycle, which helps to sustain a temperate climate with liquid water and life. So, in order to search for potentially habitable Earth-like planets, we need “a day at the beach,” where land and sea can coexist.
Previous research has cautioned that such beach-friendly worlds may be extremely rare, even in the habitable zones around the most common types of stars (namely red dwarfs). This is due to a significant difference in the water content of rocky materials found in the inner and outer parts of a protoplanetary disk where planets form, resulting in the creation of planets with either too much or too little water in most situations.
But new numerical simulations conducted by Tadahiro Kimura from the University of Tokyo and Masahiro Ikoma from the National Astronomical Observatory of Japan provide a sunnier view. By taking into consideration water produced from interactions between the still-molten surface of a young planet and its primordial atmosphere, the team found that a wide range in final water content is expected.
And within that range, several percent of roughly-Earth-sized planets in habitable zones should have appropriate amounts of water for a temperate climate. This is a high enough percentage that ongoing and future exoplanet survey missions like