Spitzer 24 μm Survey of Debris Disks in the Pleiades

Abstract

We performed a 24 micron 2 Deg X 1 Deg survey of the Pleiades cluster, using the MIPS instrument on Spitzer. Fifty four members ranging in spectral type from B8 to K6 show 24 micron fluxes consistent with bare photospheres. All Be stars show excesses attributed to free-free emission in their gaseous envelopes. Five early-type stars and four solar-type stars show excesses indicative of debris disks. We find a debris disk fraction of 25 % for B-A members and 10 % for F-K3 ones. These fractions appear intermediate between those for younger clusters and for the older field stars. They indicate a decay with age of the frequency of the dust-production events inside the planetary zone, with similar time scales for solar-mass stars as have been found previously for A-stars.