Astronomers have discovered over 5.000 exoplanets, or planets beyond our solar system, and suspect there are probably over a trillion in our Milky Way Galaxy alone. Now, scientists have identified two "water worlds".
Water could make up as much as half the mass of these planets.
"It's the best evidence for water worlds, a type of planet that astronomers thought existed for a long time," said Björn Benneke, an exoplanet researcher at the University of Montreal who was involved in the research. The research posted this week in the scientific journal Nature.
Οι πλανήτες ονομάζονται Kepler-138 c και Kepler-138 d. Ονομάστηκαν έτσι από το διαστημικό τηλεσκόπιο Kepler της NASA, το οποίο μέχρι σήμερα έχει εντοπίσει χιλιάδες εξωπλανήτες και έφερε επανάσταση στην αντίληψή μας για το τι βρίσκεται πέρα από το ηλιακό μας σύστημα, στο βαθύ σύμπαν.
These two water worlds reside in a solar system 218 light-years away and are "unlike any planet in our solar system," he says the European Space Agency.
Το διαστημικό τηλεσκόπιο Kepler όπως προαναφέραμε ανακάλυψε αυτούς τους πλανήτες. Οι αστρονόμοι όμως στη συνέχεια κοίταξαν βαθύτερα αυτούς τους κόσμους τόσο με το διαστημικό τηλεσκόπιο Hubble όσο και με το διαστημικό τηλεσκόπιο Spitzer της NASA.
They discovered that the exoplanets are three times the size of Earth, but had much less mass, which means they are less dense.
This was an interesting observation: Until now, planets slightly larger than Earth appear to be rocky worlds (also known as “super-Earths”). However, Kepler-138 c and Kepler-138 d are more similar to our solar system's ice-covered moons, such as Jupiter's Europa and Saturn's Enceladus. These moons shoot icy particles into space. Planetary scientists suspect that oceans may exist beneath the icy surface of these moons.
But Kepler-138 c and Kepler-138 d show more thermal energy than these icy moons.
"Imagine larger versions of Europa or Enceladus, the water-rich moons that orbit Jupiter and Saturn, but that are much closer to their star," said Caroline Piaulet, a scientist at the Institute for Exoplanet Research at the University of Montreal. , who led the research.
"Instead of a frozen surface, they host water vapor." The scientist refers to an atmosphere with a lot of moisture in the air as Kepler-138 d is extremely hot. Therefore its atmosphere could be water vapor.
Two super-Earth exoplanets orbiting a red dwarf star may be "water worlds." They are 218 light-years away in the constellation Lyra, and are unlike any planet found in our solar system. https://t.co/vz4ahF6ytB pic.twitter.com/NNdv7OyzAT— NASA Exoplanets (@NASAExoplanets) December 15, 2022
What's important about these latest observations of Kepler-138 c and Kepler-138 d is that scientists haven't directly detected water on the planets. But simulations of what these worlds look like – based on their mass, size and other factors – suggest they are made of “materials that are lighter than rock but heavier than hydrogen or helium,” the European Space Agency explains .
"The most common candidate material is water."