Astronomers have weighed DH Tauri's companion and have found that it is a brown dwarf with only 40 times the mass of Jupiter.

DH Tauri is a young star only one million years old in the constellation Taurus. It is so young it will not begin nuclear fusion for another one hundred million years. It is 460 light years away and two thirds as massive as the Sun. It's companion is among the coolest and lightest of known brown dwarfs orbiting young stars. If the companion had been less massive it probably would have been a planet.

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More info: Subaru telescope web page