GL 229B: An Elusive Brown Dwarf?

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.