Using the MIPS instrument on the Spitzer  telescope , we have searched for infrared excesses around a sample of 82 stars , mostly F , G , and K main-sequence field stars , along with a small number of nearby M stars .
These stars were selected for their suitability for future observations by a variety of planet-finding techniques .
These observations provide information on the asteroidal and cometary material orbiting these stars - data that can be correlated with any planets that may eventually be found .
We have found significant excess 70 µm emission toward 12 stars .
Combined with an earlier study , we find an overall 70 µm excess detection rate of 13 \pm 3 % for mature cool stars .
Unlike the trend for planets to be found preferentially toward stars with high metallicity , the incidence of debris disks is uncorrelated with metallicity .
By newly identifying 4 of these stars as having weak 24 µm excesses ( fluxes \sim 10 % above the stellar photosphere ) , we confirm a trend found in earlier studies wherein a weak 24 µm excess is associated with a strong 70 µm excess .
Interestingly , we find no evidence for debris disks around 23 stars cooler than K1 , a result that is bolstered by a lack of excess around any of the 38 K1-M6 stars in 2 companion surveys .
One motivation for this study is the fact that strong zodiacal emission can make it hard or impossible to detect planets directly with future observatories like the Terrestrial Planet Finder ( TPF ) .
The observations reported here exclude a few stars with very high levels of emission , > 1,000 times the emission of our zodiacal cloud , from direct planet searches .
For the remainder of the sample , we set relatively high limits on dust emission from asteroid belt counterparts .