Astronomers Spot ‘Toddler’ Planet Next To The Binary Star System CS Cha

The still growing exoplanet was found by chance near the double-star system, which lies less than 600 light-years away from Earth.

An artist's illustration of a binary star system with a close orbiting planet.
Marc Ward / Shutterstock

The still growing exoplanet was found by chance near the double-star system, which lies less than 600 light-years away from Earth.

Astronomers from the Leiden University in the Netherlands have photographed what seems to be a “toddler” exoplanet, reports the Dutch news outlet Astronomie.

According to the website, which is run by the Netherlands Research School for Astronomy, the researchers made this remarkable discovery completely by chance, while examining the nearby CS Cha binary star system.

This double-star system is located about 538 light-years away from Earth, in the Chameleon constellation. The team initially set out to study CS Cha in order to see whether its young stars, no older than two to three million years, are surrounded by a protoplanetary disk of dust and gas that may be giving rise to new planets.

While investigating the star system with the European Southern Observatory’s Very Large Telescope (VLT) in Chile, they uncovered that CS Cha does, in fact, have a dust disk, which surrounds both stars at the same time and is known as a circumbinary disk, Science Alert reports.

Next to the circumbinary disk the Dutch astronomers discovered an unexpected companion — an object 20 times the mass of Jupiter, notes Newsweek.

Orbiting the star system at 200 times the distance between Earth and the sun, the newfound object is big enough to be either a super-Jupiter or a small brown dwarf star.

However, astronomers are leaning towards the idea that CS Cha’s companion is a “toddler” exoplanet because VLT’s SPHERE instrument revealed it has its own dust disk surrounding it. This suggests that the newfound object is a young planet still in the making and that it could be amassing more dust and gas to grow even bigger.

For now, there’s no way of being certain of its true identity because the cloud of dust obscures much of the object’s emitted light, preventing astronomers from getting a detailed view.

“The tricky part is that the disk blocks a large part of the light and that is why we can hardly determine the mass of the companion,” said Christian Ginski, one of the Leiden astronomers that made the discovery.

Ginski explains that, in view of the circumstances, the “classical planet-forming-models” are of no use in determining the nature of CS Cha’s companion.

“It could be a brown dwarf but also a super-Jupiter in his toddler years.”

The discovery of the possible “toddler” exoplanet is detailed in a paper due to be published in the journal Astronomy & Astrophysics.

To make sure that what they uncovered was a stable companion of the CS Cha star system and not just some random object that happened to be transiting it, the Dutch team went over older photographs of the binary taken by the VLT some 11 years ago. Additionally, they also checked 19-year-old snapshots captured by the Hubble Space Telescope.

By comparing the fresh and old footage, the astronomers were able to see that the object is actually moving with the binary “and that they belong together,” notes Astronomie.

The Dutch news outlet has published two infrared images of the binary and its companion, taken with different polarization filters that reveal the objects’ respective dust disks.