Brown Dwarfs Are Hiding in Plain Sight in Our Solar Neighborhood

Discovering new brown dwarfs will help scientists to better quantify the frequency at which they occur both in our solar neighborhood and beyond. Knowing the abundance and distribution of brown dwarfs provides key information on the distribution of mass in the universe, and on the mechanism of brown dwarf formation, for example, whether they form in isolation or instead are ejected from larger planetary systems.

To that end, the team, led by Jasmin Robert of Université de Montréal, believed that although hundreds of ultracool brown dwarfs have already been discovered, the techniques used to identify them were overlooking those with more-unusual compositions, which would not show up in the color-based surveys generally used.

So they surveyed 28 percent of the sky and discovered 165 ultracool brown dwarfs, about a third of which have unusual compositions or other peculiarities. When talking about brown dwarfs, ultracool means temperatures under about 3,500 Fahrenheit or 2,200 kelvin

“The search for ultracool brown dwarfs in the neighborhood of our own Solar System is far from over,” said Gagné. “Our findings indicate that many more are hiding in existing surveys.”

This work was supported by the Fonds de Recherche Québécois-Nature et Technologie and the Natural Science and Engineering Research Council of Canada.