This system, designated RX J0806.3+1527, was first discovered as an X-ray source of variable brightness - once every five minutes, it "switches off" for a short moment. The new observations have shown beyond doubt that this period reflects the orbital motion of two "white dwarf" stars that revolve around each other at a distance of only 80,000 km. Each of the stars is about as large as the Earth and this is the shortest orbital period known for any binary stellar system.
The VLT spectrum displays lines of ionized helium, indicating that the presence of an exceedingly hot area on one of the stars - a "hot spot" with a temperature of approx. 250,000 degrees. The system is currently in a rarely seen, transitory evolutionary state.
The full text of this ESO Press Release, with two photos and all weblinks, is available at:
http://www.eso.org/outreach/press-rel/pr-2002/pr-06-02.html