Astronomers have discovered a whole new class of alien planet: a vast population of Jupiter-mass worlds that float through space without any discernible host star, a new study finds.
While some of these exoplanets could potentially be orbiting a star from very far away, the majority of them most likely have no parent star at all, scientists say.
And these strange worlds aren’t mere statistical anomalies. They likely outnumber “normal” alien planets with obvious parent stars by at least 50 percent, and they’re nearly twice as common in our galaxy as main-sequence stars, according to the new study. [Photos: The Strangest Alien Planets]
Astronomers have long predicted the existence of free-flying “rogue alien planets.” But their apparent huge numbers may surprise many researchers, and could force some to rethink how the planets came to be.
“Previous observations of bound planets tell us only about planets which are surviving in orbits now,” said study lead author Takahiro Sumi, of Osaka University in Japan. “However, [these] findings inform us how many planets have formed and scattered out.”