Researchers found a lonely planet free-floating through space without a nearby star.
The planet, called PSO J318.5-22, is about 80 light-years away from Earth. It is believed to have formed around 12 million years ago, making it relatively young as far as planets go. It has properties similar to the gas giants normally seen orbiting young stars, a University of Hawaii Institute of Astronomy news release reported.
"We have never before seen an object free-floating in space that that looks like this. It has all the characteristics of young planets found around other stars, but it is drifting out there all alone," team leader Doctor Michael Liu of the Institute for Astronomy at the University of Hawaii at Manoa, said. "I had often wondered if such solitary objects exist, and now we know they do."
Over a thousand new planets have been discovered over the past decade, but only a few have been directly imaged. All of the planets that have been imaged orbit
"Planets found by direct imaging are incredibly hard to study, since they are right next to their much brighter host stars. PSO J318.5-22 is not orbiting a star so it will be much easier for us to study. It is going to provide a wonderful view into the inner workings of gas-giant planets like Jupiter shortly after their birth," said Doctor Niall Deacon of the Max Planck Institute for Astronomy in Germany and a co-author of the study.
Researchers discovered PSO J318.5-22 while they were on the hunt for brown dwarfs (failed stars). These objects are fairly cool, which causes them to give off a faint red glow. They noticed PSO J318.5-22 was much redder than what they would expect from a brown dwarf.
"We often describe looking for rare celestial objects as akin to searching for a needle in a haystack. So we decided to search the biggest haystack that exists in astronomy, the dataset from PS1," Doctor Eugene Magnier of the Institute for Astronomy at the University of Hawaii at Manoa and a co-author of the study said.