ASTRONOMY:
Binaries Answer Riddle of Brown Dwarf Origins
Alexander Hellemans
A brown dwarf is a poor excuse for a star, being too small for gravity to ignite its nuclear furnace, but two recent studies, one of them in this issue of Science, have shown that brown dwarfs can form on their own out of interstellar gas and dust, just like real stars. One team discovered a binary brown dwarf, which would be unlikely to form other than from collapsing gas clouds as stars do. The other team reports on page 1309 that it has found a tiny brown dwarf circling a star that is too young for the dwarf to have formed from the debris swirling around it, as a planet would.