A study led by astronomers at Monash University has released new near-infrared images of the HD 169142 system confirming the formation of a protoplanet in the system. The research team used data about a star surrounded by a protoplanetary disk 350 light-years away from the European Southern Observatory’s Very Large Telescope (VLT) in Chile.

“We expect the planets to be hot during their formation, and the telescope observed HD 169142 in the near infrared to look for signs of planet formation around the star.” Nominated by Ian Hammond of the Monash University School of Physics and Astronomy.

Images captured in the VLT by the SPHERE instrument show the compact source moving for four years (2015-2019). “We have successfully discovered a protoplanet at a distance of about 37 AU. It is (slightly further from Neptune’s orbit) away from the star for four observations and orbits its parent star at the expected speed given by Kepler’s third law.’

“This confirms previous observations published in Gratton et al. (2019), which claims preliminary detection of a protoplanet.” The new study supports this hypothesis by reanalyzing the data used in their study and including new, higher quality observations.

Only two other exoplanets have been imaged during their formation: PDS 70 b and c, both orbiting the star PDS 70. This latest discovery of HD 169142 b brings that number to three. The researchers also found that as the planet pulls material from the disk, it opens up a gap (a ring-like structure) in the disk.

“In the near infrared, we can see a planet-excited spiral arm in the disk, strongly suggesting that other protoplanetary disks containing similar spirals may contain as yet undiscovered planets,” Ian said.

The spectrum shows that the planet is surrounded by a large amount of dust that reflects the light of the stars. This is to be expected if the planet is buried in a significant amount of dust it has accumulated from the disk.

“This planet is also an interesting target for the recently deployed James Webb Space Telescope.” JWST’s high sensitivity will allow researchers to detect hot dust around the planet. The material is expected to form a circular disk (a disk around the planet itself) that can form small moons like moons. This new detection proves that it is possible to directly image such formed planets, even if they are still completely buried in dust.