Astronomers spot first lunar disk around alien world
Astronomers have discovered the first disc surrounding a planet outside the solar system.
The impressive circumplanetary disk is about 500 times the size of rings of saturn and encircles a Jupiter-like planet dubbed PDS 70c. Scientists have seen numerous disks surrounding distant stars, and disks forming the moon around planets like this have previously been suspected, but this is the first time such a system has been definitively identified, the researchers say.
“Our work presents a clear detection of a disk in which satellites could form,” said Myriam Benisty, lead author of the study, astronomer at the University of Grenoble and the University of Chile in a report. declaration.
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PDS 70c is one of two young gas giants located about 400 light years from Earth. This world and its counterpart, the PDS 70b, are still in the early stages of formation and provide a unique research opportunity to study planets and moons in their infancy.
“More than 4000 exoplanets have been found so far, but they have all been detected in mature systems, ”Miriam Keppler, study co-author and researcher at the Max Planck Institute for Astronomy, said in the same release. This is not the case for the two planets observed by current research. “PDS 70b and PDS 70c, which form a system reminiscent of the Jupiter-Saturn pair, are the only two exoplanets detected to date that are still forming. ”
Using the Atacama Large Millimeter / submillimeter Array (ALMA), based at the European Southern Observatory (ESO) in the Atacama Desert in northern Chile, scientists were able to measure the diameter of the disc to be roughly the same as the distance Between Earth and the Sun (1 astronomical unit, or approximately 92,955,807 miles or 149,597,870 kilometers). The researchers also found that the disc contained enough material to form up to three satellites the size of Earth’s moon.
Unlike its companion, the PDS 70b is discless. High resolution ALMA observations indicate that PDS 70b was likely deprived of disk construction dust by PDS 70c during its initial formation.
“These new observations are also extremely important in proving theories of the formation of the planets which have not been able to be tested so far,” said Jaehan Bae, co-author and astronomer at the Carnegie Institution for Science, in the same release.
Scientists believe that the planets settle down in dusty disks around young stars, making their way through their orbit and gorging on matter as they go. As a planet grows, it can then form its own circumplanetary disk which continues to supply the young planet with gas and dust. Inside this disc, gas and dust particles also collide and can form larger and larger bodies, eventually leading to the birth of moons. However, astronomers have not yet fully understood and observed these processes.
“In short, it is still not clear when, where and how planets and moons form,” Stefano Facchini, an astrophysics researcher at ESO and co-author of the research, said in the same statement. The latest observations from PDS 70b and PDS 70c help shed light on such training processes.
Researchers hope they can revisit the pair using ESO’s extremely large telescope (ELT), which is currently under construction on Cerro Armazones, a peak in the Chilean Atacama Desert.
“The ELT will be the key to this research because, with its much higher resolution, we will be able to map the system in great detail,” Richard Teague, co-author of the study and member of the Center for Astrophysics at Harvard and the Smithsonian.
The research is described in a new study published July 22 in The Astrophysical Journal Letters.
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