# Evolution of Mid-IR Excess Around Sun-like Stars: Constraints on Models of Terrestrial Planet Formation

December 9, 2007
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We report observations from the Spitzer Space Telescope (SST) regarding the frequency of 24 micron excess emission toward sun-like stars.

Our unbiased sample is comprised of 309 stars with masses 0.7-2.2 Msun and ages from <3 Myr to >3 Gyr that lack excess emission at wavelengths <=8 microns.

We identify 30 stars that exhibit clear evidence of excess emission from the observed 24/8 micron flux ratio. The implied 24 micron excesses of these candidate debris disk systems range from 13 % (the minimum detectable) to more than 100 % compared to the expected photospheric emission.

The frequency of systems with evidence for dust debris emitting at 24 micron ranges from 8.5-19 % at ages <300 Myr to < 4 % for older stars.

The results suggest that many, perhaps most, sun-like stars might form terrestrial planets.

SpaceRef staff editor.