We present the discovery of debris systems around three solar mass stars based upon observations performed with the Spitzer Space Telescope as part of a Legacy Science Program , “ the Formation and Evolution of Planetary Systems ” ( FEPS ) .
We also confirm the presence of debris around two other stars .
All the stars exhibit infrared emission in excess of the expected photospheres in the 70 \mu m band , but are consistent with photospheric emission at \leq 33 ~ { } \mu m. This restricts the maximum temperature of debris in equilibrium with the stellar radiation to T < 70 K. We find that these sources are relatively old in the FEPS sample , in the age range 0.7 - 3 Gyr .
Based on models of the spectral energy distributions , we suggest that these debris systems represent materials generated by collisions of planetesimal belts .
We speculate on the nature of these systems through comparisons to our own Kuiper Belt , and on the likely planet ( s ) responsible for stirring the system and ultimately releasing dust through collisions .
We further report observations of a nearby star HD 13974 ( d = 11 pc ) that is indistinguishable from a bare photosphere at both 24 \mu m and 70 \mu m. The observations place strong upper limits on the presence of any cold dust in this nearby system ( L _ { IR } / L _ { \star } < 10 ^ { -5.2 } ) .