We have used the Keck I telescope to image at 11.7 \mu m and 17.9 \mu m the dust emission around \zeta Lep , 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 \mu m. The dust distance from the star is probably { \leq } 6 AU , although some dust may extend to 9 AU .
The mass of observed dust is \sim 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 \times 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 \sim 300 Myr .
This mass is approximately 200 times that contained within the main asteroid belt in our solar system .