Scientists have found evidence of the first ever planetary-mass object beyond our solar system. And it’s huge. Probably a dozen times bigger than Jupiter, according to the researchers at the National Radio Astronomy Observatory. They’re calling it a ‘rogue’ planet because it appears to be travelling through space without any kind of orbit around a parent star.
‘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, led the 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. Kao’s team used a radio astronomy observatory located in central New Mexico called – fittingly – the ‘Very Large Array’ (VLA) to pick up its magnetic activity and study it. “This particular object is exciting because studying its magnetic dynamo mechanisms can give us new insights on how the same type of mechanisms can operate in extrasolar planets — planets beyond our Solar System, Kao said.
The research shows this object (which has been designated SIMP J01365663+0933473) has a magnetic field over 200 times more powerful than Jupiter’s. Although this particular object was first picked up on in 2016, it was thought to be one of five recently discovered brown dwarfs. But this new data seems to show it’s a much younger object and its mass was therefore a lot smaller – meaning it could theoretically be classified as a planet in its own right. At 200 million years old and 20 light-years from Earth, the object has a surface temperature of about 825 degrees Celsius, or more than 1500 degrees Fahrenheit. By comparison, the Sun’s surface temperature is about 5,500 degrees Celsius.
Zeroing in on this new find could lead to new techniques being developed to help search for alien worlds. “Detecting SIMP J01365663+0933473 with the VLA through its auroral radio emission also means that we may have a new way of detecting exoplanets, including the elusive rogue ones not orbiting a parent star,” said Gregg Hallinan, from Caltech, who was part of the research team contributing to the discovery that was published in the Astrophysical Journal.