Scientists Discover Second Brown Dwarf in Space, and it's a Twin!

Nearly three decades after astronomers discovered the first brown dwarf, scientists have found a second. It’s orbiting so close to its twin that they couldn’t previously tell that this was a binary system and not a single object in space. 

A brown dwarf is an object in space too large to be a planet but too little to be a sun. Scientists call brown dwarfs “failed stars” because they develop like stars due to gravitational collapse. But they never gain enough mass to ignite through nuclear fusion. That means they glow dimly instead of shining brightly.

The brown dwarf Gliese 229B is about 19 light-years from Earth in the constellation Lepus. Before its discovery in 1995, proof of brown dwarfs did not exist. The finding that Gliese 229B is two brown dwarfs was confirmed in two studies using telescopes in Chile and Hawaii.  

"Gliese 229B was considered the poster-child brown dwarf," said California Institute of Technology researcher Jerry W. Xuan in a statement. He's a study leader. "And now we know we were wrong all along about the nature of the object. It's not one but two." 

Xuan’s study was published in the journal Nature. The other was published in the journal Astrophysical Journal Letters.

The two brown dwarfs orbit each other every 12 days at a distance of 3.8 million miles. That's roughly 16 times the distance between Earth and the moon. That’s a very close gap in space, experts say. The mass of Gliese 229Ba is 38 times larger than Jupiter. Gliese 229Bb is 34 times bigger.

Xuan told Reuters there's much more to learn about brown dwarfs. “We should always be open to surprises," he said.

Reflect: Why might it be important for scientists to discover new objects in space? What can we learn from them?

Photo of artwork showing a pair of celestial objects called brown dwarfs, named Gliese 229Ba and Gliese 229Bb from Reuters.