Record number of 'rogue planets' detected by astronomers

Telescopes at the European Southern Observatory (ESO) have observed the largest group of rogue planets ever discovered.

Rogue planets are exoplanets similar in size to planets found in our Solar System but are found with no host star to orbit. Relatively few have been discovered until recently when telescopes from the ESO and other facilities observed at least 70 new rogue planets in our galaxy, and potentially up to 170, the largest group ever discovered.

The planets are generally difficult to observe as they have no light from nearby stars illuminating them. Nuria Miret-Roig, the lead author of a recently published study in Nature Astronomy, used data spanning twenty years from various telescopes to observe the planets' glow from the heat following their formation, that would have shone for a few million years.

"We did not know how many to expect and are excited to have found so many. We measured the tiny motions, the colours and luminosities of tens of millions of sources in a large area of the sky. These measurements allowed us to securely identify the faintest objects in this region, the rogue planets," said Miret-Roig.

Researchers suspect several billions of these potential stars could be roaming the Milky Way, yet to be detected. It is unknown whether they form from collapsed gas clouds, too small to form a star or may have been ejected from a parent system.

You can read more from the study here.