Scrutinizing digitized images of the southern sky, Ben R. Oppenheimer of the University of California at Berkeley and his colleagues discovered 38 previously unnoticed cool white dwarfsfaint stellar remnants dating back some 10 to 13 billion years agoin a small portion of the halo of dark matter encircling the Milky Way. If this density of white dwarfs accurately reflects that of the rest of the halo, then they can account for at least 3 percent and perhaps up to 35 percentof the galactic dark matter.
The significance of the new findings could be far-reaching. "This research is not just about white dwarfs and dark matter. It also has implications for the star formation history of the galaxy, probably even before the disk itself formed," team member Didier Saumon of Vanderbilt University remarks. "There is much to learn about how galaxies form, and about how stars form in the process, from studying this population of white dwarfs."