PSO J318.5-22 is an independent planet who don't need no star.
As far as planets go, PSO J318.5-22 has scientists perplexed and excited. The 12 million-light-year-old planet, young by planetary terms, is only 80 light-years from Earth and has similarities to gas-giant planets orbiting young stars. However, this one is not orbiting around a star.
"We have never before seen an object free-floating in space that looks like this," Dr. Michael Liu, team leader of the Institute for Astronomy at the University of Hawaii at Manoa, said. "It has all the characteristics of young planets found around other stars, but it is drifting out there all alone. I had often wondered if such solitary objects exist, and now we know they do."
Dr. Niall Deacon of the Max Planck Institute for Astronomy in Germany and co-author of the study said studying planets via direct imaging is difficult because they are next to their brighter host stars. Because PSO J318.5-22 is not near a star, it will be easier to examine. Deacon said they will study the planet to gain insight on the "inner workings of gas-giant planets like Jupiter shortly after their birth."
Astronomers first found the planet when they were searching for brown dwarfs, failed stars. Further observation showed it to be a low-mass planet. The astronomers have placed it within a collective of young stars called the Beta Pictoris, a moving group of stars that formed 12 million years ago. A young gas-giant is in orbit around Beta Pictoris, but scientists concluded PSO J318.5-22 is lower in mass and probably formed in a different fashion.
The discovery paper is available at http://arxiv.org/abs/1310.0457 and is being published by Astrophysical Journal Letters.