Astronomers have discovered a lonely planet outside the solar system, which is floating freely in space and not orbiting a star.
The free-floating planet without has been dubbed PSO J318.5-22 and is 80 light years away from Earth. The planet without a host star also has a mass that is six times that of Jupiter. Apparently, according to researchers, the planet formed barely 12 million years ago, which makes it a newborn in planet lifetimes.
So how did researchers, whose study was published in "The Astrophysical Journal Letter", chance across the planet? The team of researchers from the Institute for Astronomy at the University of Hawaii identified PSO J318.5-22 from its "faint and unique heat signature" via the Pan-STARRS 1 (PS1) wide-field survey telescope on Haleakala, Mau. PSO J318.5-22 was discovered "during a search for failed stars" that are also known as brown dwarfs.
"We have never before seen an object free-floating in space that looks like this. It has all the characteristics of young planets found around other stars, but it is drifting out there all alone," said research team leader Michael Liu of the Institute for Astronomy at the University of Hawaii. "I had often wondered if such solitary objects exist, and now we know they do."
The researchers also discovered that the free-floating planet had properties similar to those of gas-giant planets that can be found orbiting young stars in the Milky Way. PSO J318.5-22 also has the distinction of being the lowest-mass free-floating object that has been discovered thus far. What is unusual, however, is the fact that the planet is by itself and does not have a host star.
"Planets found by direct imaging are incredibly hard to study, since they are right next to their much brighter host stars," study co-author Niall Deacon of the Max Planck Institute for Astronomy in Germany said. "PSO J318.5-22 is not orbiting a star so it will be much easier for us to study."
The discovery of the free-floating PSO J318.5-22, which lacks a host star, is being seen as a blueprint which will give researchers key insights into how gas-giant planets develop post their birth.
