GL 229B: An Elusive Brown Dwarf?

About This Image

What type of matter makes up most of the universe? This question is arguably the most perplexing astronomical mystery of our time. A leading candidate is a type of dim, low mass star called a "brown dwarf" star. Our universe could contain more brown dwarfs than any other type of star - but they are so dim they have so far escaped detection. The dramatic photograph above, taken in October 1994, sheds new light on this "dark matter" problem. The seemingly inconspicuous companion to the right of the overexposed image of a normal star is thought to be an elusive brown dwarf. Now that the existence of brown dwarfs has been demonstrated, a key remaining question is their abundance.