astronomy where the moons are born

Perhaps the precursors to satellites are already forming there: For the first time, astronomers are projecting clear images of the moon-forming disk of dust around a young exoplanet. According to the data, their mass is enough to give a celestial body like Jupiter three satellites the size of our moon. Scientists say the observations can now help us understand evolution in young planetary systems.

Jupiter and Saturn are with them: in addition to the planets, about 170 moons make up the worlds of our Solar System. There are really exciting specimens: the moons Enceladus and Europa may have liquid water in their interior and thus come into question as potential extraterrestrial habitats. It can be assumed that many planets in distant star systems are orbited by moons. So far, however, no axomonds have been definitively detected and their possible academic history also appears to be unclear.

In the case of our Earth’s moon, it is thought to have formed as a result of Earth colliding with a Mars-sized protoplanet. In the case of satellites of the gas giants, however, proceeds from a different story: according to this, the planets initially formed by collecting more and more matter into the so-called circumstellar disk of dust around the Sun. During this evolution process, a planet may also generate its so-called perihelion disk, from which material gradually collapses at the center. At the same time, the gas and dust in the perihelion disk can also mix together to form larger and larger structures, which eventually lead to the birth of moons. That’s the principle. But there are still many unanswered questions about when, where and how planets and moons form.

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A closer look at a youth system

For the past few years, two planets in the young PDS 70 star system have been under the attention of an international team of astronomers because of their potential insights. “So far more than 4,000 exoplanets have been found, but all of them have been discovered in evolved systems. PDS 70 b and PDS 70 c, which form a system that is reminiscent of the Jupiter-Saturn pair, have been discovered so far. There are only two exoplanets that are still in the process of formation,” explains co-author Miriam Kepler from the Max Planck Institute. Astronomy in Heidelberg. In early 2019, astronomers presented evidence of a potentially moon-forming disk around PDS 70c. Since they could not clearly distinguish the disc from its surroundings, there was no clear evidence until now and no more detailed information was available.

“Our work is now a clear confirmation,” says first author Miriam Benisti from the University of Grenoble. The Atacama Large Millimeter/submillimeter Array (ALMA) enabled a closer look at the system. “Our data were obtained with such excellent resolution that we could clearly see that the discs are associated with the planet. We have also been able to deduce their size for the first time,” says Benisti.

Materials for Earth’s three moons

ALMA data show that the perihelion disk has a diameter roughly the same as the distance from our Sun to Earth. So the planet has a wide area around it: the disk around PDS 70c is about 500 times larger than the rings of Saturn. Astronomers report that it was also possible to draw conclusions about the mass of the contained matter. Co-authors from the Harvard-Smithsonian Center for Astrophysics explain, “We used emission data from the dust grains to estimate how much mass is in the disk, resulting in the potential for lunar system formation around PDS 70c.” Reservoir.” in Cambridge. So we have enough material available to produce three celestial bodies the size of Earth’s Moon.

In addition to evidence of a lunar birth zone around PDS 70c, scientists were now able to clearly demonstrate the lack of a circumplanetary disk in the case of the neighboring planet PDS 70b. It also provides interesting clues: according to scientists, PDS 70c could have been carrying back dust from its neighboring planet from which it originated.

They hope to gain an even deeper understanding of the exciting planetary system from future observations with the European Southern Observatory ESO’s Extremely Large Telescope (ELT), which is currently being built on Cerro Armazone in the Chilean Atacama Desert. Above all, they intend to use it to probe the gas movements around PDS 70c to obtain a complete 3D image of the system. “The ELT will be the key to this research because, with its much higher resolution, it will allow us to map the system in great detail,” says co-author Richard Teague of the Harvard-Smithsonian Center for Astrophysics.