Closer view of the young giant planet PDS 70c (bright dot), with the circumplanetary disk of dust and rocky debris around it. There is enough material in the disk for three moons the size of our own moon. Image via ALMA (ESO/ NAOJ/ NRAO)/ Benisty et al.
There are hundreds of moons in our solar system, from the size of asteroids to larger than Mercury. What about distant solar systems? Do their planets have moons, too? Astronomers have discovered thousands of exoplanets, or worlds orbiting distant stars. And it would seem logical that some should have moons – exomoons – also. So far, though, astronomers haven’t confirmed any exomoon. Such moons would tend to be smaller than their planets, and exoplanets themselves aren’t easy to find. But now, astronomers have found the first clear evidence of a moon-forming disk around a young giant exoplanet. The European Southern Observatory announced the exciting finding on July 22, 2021.
The star is PDS 70, a very young, newly formed T Tauri star in the direction to our constellation Centaurus, located nearly 400 light-years away. The planet is called PDS 70c. It’s one of two giant, Jupiter-like planets orbiting this young star.