A possible massive asteroid belt around ζ Leporis

We have used the Keck I telescope to image at 11.7 and 17.9 mum the dust emission around zeta Leporis, a main-sequence A-type star at 21.5 pc from the Sun with an infrared excess. The excess is at most marginally resolved at 17.9 mum. The dust distance from the star is probably less than or equal to6 AU, although some dust may extend to 9 AU. The mass of observed dust is similar to 10(22) g. Since the lifetime of dust particles is about 10(4) yr because of the Poynting-Robertson effect, we robustly estimate at least 4 x 10(26) g must reside in parent bodies, which may be asteroids if the system is in a steady state and has an age of similar to 300 Myr. This mass is approximately 200 times that contained within the main asteroid belt in our solar system.