Researchers Just Discovered Dozens Of Starless Rogue Planets In Our Galaxy

Astronomers have discovered dozens of new "rogue" planets. These cosmic bodies roam around freely by themselves instead of orbiting around a star.

Astronomers have discovered dozens of new "rogue" planets in a new finding that is being described as an important step towards a better understanding of these cosmic objects. Rogue planets are rare cosmic bodies that are comparable in mass to regular planets but do not have a star to orbit around. Instead, they roam freely on their own in space in what is thought to be a relatively rare occurrence for such large celestial bodies.

Researchers over the years have found thousands of exoplanets, but almost all of them orbit around a star, just like the earth and other planets in this solar system orbit around the sun. While astronomers believe that such rogue planets are fairly common, not many were known before the latest discovery, which is why these findings hold utmost significance.

The new rogue exoplanets were discovered by a team of researchers led by Núria Miret-Roig, an astronomer at the Laboratoire d’Astrophysique de Bordeaux, France and the University of Vienna, Austria. Their study, which was published this week in Nature Astronomy, claims to have found "at least 70" of these cosmic bodies that have masses comparable to that of Jupiter. The total number could even be as high as 170 because it's not immediately possible to tell which of these objects qualify as a planet and which ones do not. They are located 420 light-years away from earth in what's described as a "star-forming region close to our Sun," within the Scorpius and Ophiuchus constellations.

The Discovery Required Twenty Years Worth Of Data

The discovery was made using data from the past twenty years from a number of telescopes, including ESO’s Very Large Telescope (VLT), the Visible and Infrared Survey Telescope for Astronomy (VISTA), the VLT Survey Telescope (VST), and the MPG/ESO 2.2-meter telescope. While rogue planets are almost impossible to spot because they are not illuminated by any star, the new group could be observed because they are still burning hot even millions of years after their formation.

According to the scientists, it's difficult to reliably count the number of rogue exoplanets they spotted as it's not possible to measure the exact masses of these objects by just observing them. With no way to gauge their exact mass, the astronomers based their estimates on the brightness of the planets. As explained by the European Southern Observatory (ESO), the brightness of a planet typically indicates its age, as older planets are less bright than the younger ones. That's because the older ones have been cooling down for longer since their formation, thus reducing their brightness. In contrast, the younger ones are still much hotter and are burning bright.

If the objects are older and still burning bright, they are likely larger than 13 times the mass of Jupiter, which disqualifies them from being counted as a planet. However, for newer objects, even the brightest ones could be well within the specified mass to be counted as a planet. So unless researchers can say with certainty whether the region is old or new, it will remain impossible to say how many of these cosmic objects are rogue exoplanets and how many of them are not. Either way, irrespective of the number, this is still a massive discovery that should aid researchers in gaining a more robust understanding of rogue planets