We just found a much easier way to find baby planets in deep space

14 Jun 2018

A forming exoplanet. Image: Dima Zel/Shutterstock

In our efforts to understand more about the origin of the universe, a new method of astronomy can help us uncover a substantial number of baby planets.

As the Kepler and Hubble space telescopes have shown us time and time again in recent years, astronomers have had no shortage in finding new worlds in deep space, with the number of known exoplanets now reaching into the thousands.

But, of that number, only a small percentage found can be categorised as ‘baby planets’, which could help answer the many outstanding questions we have about planet formation, especially within our own solar system.

This could all be about to change after an international team of astronomers revealed that it used archival radio telescope data to develop a new method for finding these very young extrasolar planets.

Publishing its findings to The Astrophysical Journal Letters, the team showed it could use the Atacama Large Millimeter/submillimeter Array (ALMA) to image these disks with never-before-seen clarity.

Baby planet forming

An artist’s impression of protoplanets forming around a young star. Image: NRAO/AUI/NSF/ S Dagnello

Method ‘will provide essential evidence’

Unlike its older counterparts, young planets are surrounded by rotating disks of gas and dust, from which planets are formed. This makes them difficult to spot using existing techniques, such as analysing emissions from a disk’s dust particles.

The problem with this method is that dust only comprises 1pc of a disk’s mass, which is why the team’s new method focuses instead on the other 99pc made up of gas.

Looking at the motion of the gas, the method probes radial pressure gradients within it to see the shape of its swirls and eddies, allowing astronomers to make a more precise determination of the masses and locations of any planets embedded in the disk.

Testing its new method, the team confirmed the previously predicted existence of two Jupiter-mass planets around HD 163296. Orbiting at distances of 83 and 137 times that between the sun and Earth, the planets’ host star is actually significantly brighter than our own parent star.

“This method will provide essential evidence to help interpret the high-resolution dust images coming from ALMA,” said the study’s lead author, Richard Teague of the University of Michigan.

“Also, by detecting planets at this young stage, we have the best opportunity yet to test how their atmospheres are formed and what molecules are delivered in this process.”

Colm Gorey was a senior journalist with Silicon Republic