Understanding the evolution of planets is one of the most important aspects of understanding planetary formation. We’ve said it before and we’ll say it again – no one set of rules or processes seems to apply to the formation of planetary systems. Our sample size of one has been proven to be an outlier of a system so far. And with bigger and better telescopes, we are getting to the point where directly imaging exoplanets is becoming more and more common, aiding us in our quest to find patterns.

Even better, we’re beginning to find incredibly young planets, and a new paper in The Astrophysical Journal Letters with lead author Feng Long has provided a potential new method to find those worlds. In this case, an exoplanet in the range of Neptune or Saturn size was discovered in the disk of planetary dust. The disk is LkCa 15, about 518 light-years away in the constellation of Taurus. Feng analyzed new high-resolution data from the ALMA Observatory to detect features that point to the presence of a planet.

The protoplanetary disk is about 42 AU from its parent star, and dust collecting in the L4 and L5 Lagrange points of the star indicates that a planet is forming in the disk. Long explains: We’re seeing that this material is not just floating around freely, it’s stable and has a preference where it wants to be located based on physics and the objects involved.

And the baby exoplanet is only about one to three million years old.

When you find one example, you know you have the tools to find another example. Scientists are continuing to push the limits of what we know, providing us with glimpses of processes long past for our own solar system that can then be applied to exoplanet populations… once we have even more examples to work with.

More Information

Center for Astrophysics | Harvard & Smithsonian press release

“ALMA Detection of Dust Trapping around Lagrangian Points in the LkCa 15 Disk,” Feng Long et al., 2022 September 14, The Astrophysical Journal Letters