A dust ring around epsilon Eridani: Analog to the young solar system

Dust emission around the nearby star epsilon Eridani has been imaged using a new submillimeter camera (the Submillimetre Common-User Bolometer Array a t the James Clerk Maxwell Telescope). At an 850 mu m wavelength, a ring of dust is seen peaking at 60 AU from the star and with much lower emission in side 30 AU. The mass of the ring is at least similar to 0.01 M-circle plus in dust, while an upper limit of 0.4 M-circle plus in molecular gas is impo sed by CO observations. The total mass is comparable to the estimated amoun t of material, 0.04-0.3 M-circle plus, in comets orbiting the solar system. The most probable origin of the ring structure is that it is a young analo g to the Kuiper Belt in our solar system and that the central region has be en partially cleared by the formation of grains into planetesimals. Dust cl earing around epsilon Eri is seen within the radius of Neptune's orbit, and the peak emission at 35-75 AU lies within the estimated Kuiper Belt zone o f 30-100 AU radius. epsilon Eri is a main-sequence star of type K2 V (0.8 M -circle dot) with an estimated age of 0.5-1.0 Gyr, so this interpretation i s consistent with the early history of the solar system where heavy bombard ment occurred up to approximate to 0.6 Gyr. An unexpected discovery is the substructure within the ring, and these asymmetries could be due to perturb ations by planets.