Dozens of wandering planets, with no host star, nearly double the number of these mysterious free-moving planets.
The set of at least 70 starless exoplanets, the largest group of rogue planets ever discovered, was found in a region of space about 420 light-years from Earth.
Lead author of the study, Núria Miret-Roig, an astronomer at the Laboratoire d\’Astrophysique de Bordeaux in France and the University of Vienna in Austria, said: “We don’t know how many planets are expected and also I’m glad to have discovered so many”.
Most exoplanets are discovered through observations of their host star. However, this method does not work with wandering exoplanets. As a result, these exoplanets are significantly more difficult to detect.
Astronomers in general have relied on a technique called gravitational microlensing, which involves observing moving foreground objects in front of background stars to find wandering exoplanets.
However, astronomer Miret-Roig’s team did not apply this method. Instead, the team analyzed 20 years’ worth of images and other data from ground- and space-based telescopes, including the European Southern Observatory’s Very Large telescope in Chile. , the Japanese Subaru telescope in Hawaii, the European Space Agency’s Gaia spacecraft and the instrument on the Victor M. Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile.
“We measured the small movements, color and brightness of tens of millions of sources in a large area of the sky. These measurements allow us to safely identify the faintest objects in this region, the wandering planets,’ said Miret-Roig.
The researchers observed infrared energy emitted from 70 to 170 roving exoplanets, and report in the new study published December 22 in the journal Nature Astronomy.