Finding young planets in our galaxy is still very much at the forefront of science.

But with the help of the world’s most expensive ground-based telescope, two teams of astronomers are convinced they’ve found not one, but three baby planets.

The young planets orbit a star called HD 163296, which is located about 330 million light years away from us in the constellation of Sagittarius (The Archer).

It’s the first time the $1.4 billion Atacama Large Millimeter/submillimeter Array (ALMA) telescope has discovered new planets, thanks to a special technique to help hunt them down.

Both teams of astronomers looked to unusual patterns in the flow of gas within a planet-forming disc around a young star. 

They studied the spread of carbon monoxide within the disc, observing the wavelengths of light emitted from molecules of the gas, which revealed how it was moving about. Any strange movements in the flow of the gas were a sign that it was in contact with a massive object.

“We looked at the localised, small-scale motion of gas in the star’s protoplanetary disc,” Richard Teague, an astronomer from the University of Michigan and author of one of the two papers on the discovery, explained in a statement online.

“This entirely new approach could uncover some of the youngest planets in our galaxy, all thanks to the high-resolution images from ALMA.” 

A team led by Teague found two planets located 12 billion and 21 billion kilometres from the star. While another team, led by Christophe Pinte of Australia’s Monash University, identified a planet situated 39 billion kilometres from the star.

“Measuring the flow of gas within a protoplanetary disc gives us much more certainty that planets are present around a young star,” Pinte added. 

“This technique offers a promising new direction to understand how planetary systems form.”