A strange lonely planet found without a star

An international team of astronomers has discovered an exotic young planet that is not orbiting a star. This free-floating planet, dubbed PSO J318.5-22, is just 80 light-years away from Earth and has a mass only six times that of Jupiter. The planet formed a mere 12 million years ago, a newborn in planet lifetimes.

“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,” explained team leader Dr. Michael Liu of the Institute for Astronomy at the University of Hawaii at Manoa. “I had often wondered if such solitary objects exist, and now we know they do.”

The discovery paper of PSO J318.5-22 is being published by Astrophysical Journal Letters and is available at http://arxiv.org/abs/1310.0457.
Image: Artist’s conception of PSO J318.5-22. Credit: MPIA/V. Ch. Quetz