They even found an example of binary planets where two planets orbit each other in the absence of a parent star. (sciencedaily.com)
We think binary planets are common in the galaxy, just as we know that binary stars are common in the galaxy, and we have even begun to find binary asteroids. (discovermagazine.com)
New observations reveal a rare binary planet system made of two gas giants four times as massive as Jupiter that likely formed in the breakup of a protostar 10 million years ago (newscientist.com)