For the first time, it has been possible to capture the formation disk of a moon on an exoplanet. This is a time machine for astronomers, as it helps them travel back in time and see what the birth of our own satellite could have been like. But not only that, it also helps to understand how planets are born.
This unprecedented find has taken place thanks to images taken by the Atacama Large Millimeter / submillimeter Array (ALMA), a large radio telescope made up of 66 antennas, managed by an international association between Europe, North America and East Asia, and in collaboration with Chile, where the instrument is located.
As for its authors, they are a group of scientists, led by Dr. Myriam benisty, from the University of Grenoble. Their results have been published today in The Astrophysical Journal Letters.
Watch out for the birth of a moon on an exoplanet
In fact, this disk of formation of a moon on an exoplanet has been sensed for a long time. However, it was impossible to distinguish from its surrounding environment. So these scientists turned to SOUL, to take clearer images, which allow better analysis. So it was.
The disk in question is located next to PDS 70c. This is a giant planet, similar to Jupiter, orbiting a star 400 light years from Earth. The star system completes it PDS 70b, which forms with its partner a planetary pair similar to that of Jupiter and Saturn in the solar system.
But this disk has only been seen in PDS 70c. The other doesn’t seem to have any. The disk has a diameter similar to the distance between the Sun and Earth and enough mass to originate up to three satellites. Therefore, his observation, unique in history, can give scientists very interesting data about how it was the birth of our moon or from any other satellite. But it can teach us more.
From the origin of satellites to the birth of planets
Jaehan bae, one of the study authors, has explained in a Press release that the discovery of the formation of a moon disk on an exoplanet may also help to “prove theories of planet formation that have not been proven until now.”
And it is that, initially, the planets are formed in disks of gas and dust around young stars. To grow, they gobble up all this material, which gradually condenses, giving rise to the planetary body. But, in turn, it can form around it its own circumplanetary disk. This, on the one hand, helps to keep it growing, by regulating the amount of material that falls on it. But, on the other hand, by generating collisions between gas and dust in this disk, one or more satellites can also form, which will become the moons of this planet.
Both are processes that still hold many mysteries for astronomers. Therefore, having the opportunity to follow the entire process is a great gift. And the best thing is that, as explained in the statement, all these data will be able to be expanded much more when the construction of the ESO’s Extremely Large Telescope (ELT), located on Cerro Armazones, also in the Chilean Atacama Desert. This journey into the past has only just begun.