Moon-Forming Disk Captured Around Exoplanets Resembling Saturn and Jupiter; PDS 70 System May Support Theories on How Planets and Moons Form

The Atacama Large Millimeter/Submillimeter Array or ALMA has recently captured the PDS 70 system, located at about 400 lightyears from our planet. The PDS 70 is comprised of a star at the center of the system, along with two planets that look like Saturn and Jupiter revolving around it.

PDS 70 System's Satellite-Forming Circumplanetary Disk

PDS 70's stunning circumplanetary disk is estimated to be 500 times larger than the ring of one of our solar system's planets, Saturn. The circumplanetary disk rotates around the planet with features like the planet Jupiter, also known as the PDS 70c. Astronomy experts have been successful in identifying cosmic disks that surround stars far away from our galaxy. Some of them even have a Moon-forming disk, but this is the first time that a planet had been discovered with its own, personal disk that was confirmed.

The University of Grenoble and the University of Chile were the prestigious institutes that have conducted this study. Based on their statement, the authors of the study are certain that the planets found in the PDS 70 have a disk that could possibly form satellites, reports VOA News.

PDS 70c, like our solar system's Jupiter, is a gas giant located 400 lightyears away from Earth. According to the study, the planet and its partner, PDS 70b, are determined to be in their early planetary stages. This means that the formation of the planets is going through their initial evolution. This change that is currently happening hundreds of lightyears away from our planet is beneficial for experts to understand more about the young planets, their moons, and their early planetary stage.

Max Planck Institute for Astronomy expert and co-author of the study Miriam Keppler said that the exoplanets identified outside of our galaxy are estimated to be up to 4,000 individual planets already, and most of them are found in mature systems. But compared to the initial exoplanets, the newly discovered PDS 70b and PDS 70c are still in the process of their early formation as reported by Space.

How Do Planets and Moon Form?

There are many theories on how planets and moons are formed, and these theories can be backed up by the findings that are expected to be provided by the PDS 70 system observations. Today, one of the most accepted theories on planetary formation is that it is a product of grains of cosmic dust which scale to the width of the human hair. This dust originates from the disks spiraling around a young star in an individual system. The factors that make the dust collide and compile with each other include the natural gravitational pull of the star itself. According to NASA, the process of collision will pile up the specks of dust and other materials available, forming a much bigger material, until it becomes a planet. Different materials also cause different structures and compositions of a planet, which we observed in the planets that we know today.

The formation of moons is also tackled in multiple theories, including the giant impact, co-formation, and capture theories. Experts also argue that moons, including ours, differ in their lunar formation. According to the giant impact, foreign materials crashed into our planet, resulting in the bits and pieces forming the moon. In co-formation theory, the satellites are formed while their parent planets are formed, too. This would explain why moons have a similar composition with their parent planet, reports Space.

Capture theory is somewhat similar to the giant impact theory, however, this theory implies that moons were already formed outside our system before it was pulled and snatched by planets that they are currently orbiting. Capture theory applies to the moons of Mars: Phobos and Deimos. Whatever theory is right, it can be proven with the substantial evidence the astronomers can get from the examinations of the PDS 70 system.

Early Formation of PDS 70 Young Planets

The Atacama Large Millimeter/Submillimeter Array, located at the European Southern Observatory ESO in the northern region of Chile, was utilized by the experts to capture and examine the features of the PDS 70 system. The measurement from the study shows that the diameter of the disk is similar to the distance between our planet and the Sun. In addition, the scientists also observed that the disk contains materials sufficient to form a maximum of three satellites with a size comparable to our moon, reports Space.

PDS 70b, compared to PDS 70c, has no disk around it. Based on ALMA's high-resolution imaging, the experts of the study theorize that the PDS 70b did not have any ring due to PDS 70c harnessing all of the dust-building disks in their initial formation.

Carnegie Institution for Science astronomy expert and co-author of the study Jaehan Bae said that the state and transition of the new planets are beneficial towards the planetary formation theories that aren't available and can't be tested before. The findings from the PDS 70 system were published in The Astrophysical Journal Letters, entitled "A Circumplanetary Disk around PDS70c."