In 2017, scientists discovered the Trappist-1 star system, an ultra-cool red dwarf 40 light years away surrounded by seven Earth-like planets. Trappist-1 has been of particular interest as the seven planets have terrestrial features which could shed light on planetary formation and potential habitability. However, the latter notion might be questionable, according to a recent study published in the journal, Nature Astronomy.
A team of researchers from Arizona State University and Vanderbilt has found evidence that suggests that the Trappist-1 exoplanets actually have too much water to support life. They were able to use data from previous efforts that focused on determining the mass and diameter of each planet to calculate densities. This data was then incorporated into a computer to model what the planets’ ingredients might look like.
According to the study, all the planets in the Trappist-1 system have more water than Earth, from 50 percent of their mass to 10 percent. To give a better picture, Earth’s mass has only 0.2 percent water.
This would mean that there is likely no exposed land, which means no geochemical cycles that could create an atmosphere.
The seven exoplanets have been classified as rocky, which means that they are not gaseous. In addition, three of them reside in the “habitable zone”, however, the Trappist-1 star is said to be 2 thousand times dimmer than our own. This would suggest that the planets that may support life have to be very close to their star. More so, red dwarf’s have been known for their massive solar flares which are likely to wipe off any signs of life on the planets.
The researchers believe that their findings could also have implications for theories on how planets develop. They note that all seven Trappist-1 planets are located within the “snow line”. This is the distance from the star beyond which water exists as ice and can be accreted into a planet. Planets inside the ice line have water in the form of vapor and will not be accreted. The study found that the Trappist-1 planets must have formed farther from their star, beyond the snow line, and migrated inwards over time.
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