A team of researchers from the Rochester Institute of Technology has discovered a still-forming substellar object just 330 light-years from Earth. This incredible find is likely to turn out to be the youngest planet so close to the Solar System.
The astronomers estimate that the object is less than 5 million years old, orbiting its star at a distance of 600 AU (1 AU, or astronomical unit, is the Earth-Sun distance). It weighs 10 times the mass of Jupiter, putting it close to the giant planet/brown dwarf boundary of 13 Jupiter masses. The discovery is reported in Research Notes of the American Astronomical Society.
“The dim, cool object we found is very young and only 10 times the mass of Jupiter, which means we are likely looking at an infant planet, perhaps still in the midst of formation,” lead author Annie Dickson-Vandervelde said in a statement. “Though lots of other planets have been discovered through the Kepler mission and other missions like it, almost all of those are ‘old’ planets. This is also only the fourth or fifth example of a giant planet so far from its ‘parent’ star, and theorists are struggling to explain how they formed or ended up there.”
The object was discovered thanks to Gaia, a European Space Agency mission that's working to produce the most detailed map of the Milky Way yet. The spacecraft is tracking the accurate positions and velocities of over a billion stars, making it an invaluable tool for a myriad of astronomical applications.
For this work, researchers used Gaia data to look for sub-stellar objects (planets or brown dwarfs) within the Epsilon Chamaeleontis Association, a nearby group of young stars. They found the potential giant planet because it moves along with the rest of this group, so it is likely to be part of it.
The newly discovered object deserves a follow-up study to help us better understand its nature, how it formed, and put limits on its actual age. Its formation history, in particular, might be key to working out if it is a brown dwarf or a gas giant planet.