Space telescopes have so far found relatively few exoplanets ranging in size from 1.3 to 2.4 Earth radii. As astronomers report, the reason for this seems to be the different composition of celestial bodies in dry rock and ice.
Most of the more than 4,000 discovered planets outside our solar system have a radius of one to four times the Earth’s. In this regard, astronomers have found planets with radius 1.3 and 2.4. “The sizes between the two peaks are much rarer and therefore form a so-called radial valley,” said first author Julia Venturini of the International Space Research Institute and the University of Bern, according to a press release from the National Research Center PlanetS.
She and her team found that planets that are only formed from dry rock remain much smaller than those that accumulate ice as they grow. This is due to the different collision properties of rock and ice.
Using computer models, they were able to recreate the Radius Valley on this basis, as reported in the specialist journal Astronomy & Astrophysics. The first common planet about 1.3 Earth radii consists of dry rocky planets, and the second group about 2.4 Earth radii consists mainly of water-rich worlds.
“These results could help us characterize planets outside our solar system,” said Venturini. However, they still need to be validated, for example with data from ESA’s planned infrared remote sensing atmosphere telescope (ARIEL).
Quelle: Co / Sda