A gray area exists between stars and planets, and what was thought to be a failed brown dwarf star has now been determined to be a massive rogue planet with an enormous gravity field.
Via the National Radio Astronomy Observatory:
"This object is right at the boundary between a planet and a brown dwarf, or 'failed star,' and is giving us some surprises that can potentially help us understand magnetic processes on both stars and planets," said Melodie Kao, who led this study while a graduate student at Caltech, and is now a Hubble Postdoctoral Fellow at Arizona State University.
Brown dwarfs are objects too massive to be considered planets, yet not massive enough to sustain nuclear fusion of hydrogen in their cores — the process that powers stars. Theorists suggested in the 1960s that such objects would exist, but the first one was not discovered until 1995. They originally were thought to not emit radio waves, but in 2001 a VLA discovery of radio flaring in one revealed strong magnetic activity.
VLA is the Very Large Array in New Mexico.
• VLA Detects Possible Extrasolar Planetary-Mass Magnetic Powerhouse (National Radio Astronomy Observatory)
Image: Chuck Carter via NRAO/AUI/NSF