Scientists at Rutgers University (USA), led by Lugendra Ojha, presenting at the Goldschmidt Geochemistry Conference in Lyon, predicted the existence of terrestrial-type exoplanets (exo-Earths) with groundwater. The results of the research were published in the journal nature communication.
Such planets revolve around red dwarfs and are outside the habitable zone, but have subterranean oceans due to geothermal heat. It is generally accepted that water only exists on planets located within the habitable zone. If the planet goes beyond its borders, no water is stored on it. However, there are exceptions. Therefore, in the solar system, icy moons revolve around Jupiter and Saturn, which are also outside the habitable zone but have subglacial oceans. Scientists have suggested that a similar process can occur on planets orbiting red dwarfs at a sufficiently large distance.
The researchers modeled the evolution of ice sheets on exo-Earths to identify the conditions that allow liquid water to exist for long periods at temperatures above the freezing point of water ice. It turns out that even with moderate geothermal activity occurring on the moons of Jupiter and Saturn, oceans of liquid water can form at the base of ice sheets. They can persist for long periods due to the slow (over billions of years) half-life of heat-producing radioactive elements.
The authors conclude that these subglacial oceans, often in contact with the planet’s crust and shielded from the high-energy radiation of the parent star by thick layers of ice, could provide favorable conditions for the existence of life.
The authors of the study emphasize that after the formation of planets, the main heat sources in them may be radioactive isotopes with long half-lives such as 40K, 232Th, 235U and 238U.
ancient scientists discovered two new Neptune six exoplanets.