Astronomers spot possible moon-forming region for the first time

While scientists have found many exoplanets over the years, they have yet to spot any moons orbiting these worlds outside of our solar system. Now, a group of astronomers have discovered (PDF) what is believed to be a region with emerging exomoons for the first time. Myriam Benisty and a team from the University of Grenoble found the dust disk – the region where the moon was formed – around a young exoplanet in a star system called PDS 70 located 370 light years from Earth.

The team found the first protoplanet (PDS 70b) in the system in 2018 using the very large telescope at the European Southern Observatory in Chile. A year later, they found another young gas giant (PDS 70c) using the same equipment. Astronomers believe, based on the data they have, that the star system is only 10 million years old, and the two gas giants are several times the size of Jupiter. To learn more about the system, they’ve focused all other possible instruments on it, including the Atacama Large Millimeter / submillimeter Array. ALMA is made up of 66 short wavelength parabolic antennas, and its observations have identified dust around the PDS 70c.

The dust disk spans a distance slightly wider than the distance between Earth and the Sun, and there is enough mass for three moons the same size as ours. Benisty says the moons may have already formed, but there is no conclusive evidence yet as they cannot be seen with ALMA. According to Science, the Extremely Large Telescope, which will be the world’s largest optical telescope when built, could have the power to see if moons have already formed around the protoplanet. However, the telescope is still under construction and science operations will not begin until 2027 at the earliest.