A Hubble Space Telescope investigation found that brown dwarfs that were originally binary systems don't stay together for long.
Brown dwarfs are interstellar objects larger than Jupiter but smaller than low-mass stars. They form from a collapsed cloud of gas and dust like stars, but they lack the mass to fuse hydrogen.
The lowest-mass and coldest brown dwarfs have few partners, according to Hubble observations. Hubble can identify binaries as close as 300 million miles, the distance between the Sun and the asteroid belt.
They didn't find any binary pairs in a solar neighborhood brown dwarf sample.
This suggests that bypassing stars pull a binary pair of dwarfs apart over a few hundred million years due to their weak gravity association.
Although binary brown dwarfs are discovered at earlier ages, our analysis shows that widely separated partners are rare among the lowest-mass and coldest lonely brown dwarfs.
"This suggests that such systems do not last," said lead scientist Clémence Fontanive of the Trottier Institute for Research on Exoplanets, Université de Montréal, Canada.
Hubble's scan of extremely young brown dwarfs a few years ago found binary partners, showing that star-forming mechanisms produce binary pairings among low-mass brown dwarfs. The absence of binary companions in older brown dwarfs shows that some started as binaries but split off.