Formation and Evolution of Planetary Systems: SIRTF Legacy Science in the VLT Era

Abstract

We will utilize the sensitivity of SIRTF through the Legacy Science Program to carry out spectrophotometric observations of solar-type stars aimed at (1) defining the timescales over which terrestrial and gas giant planets are built, from measurements diagnostic of dust/gas masses and radial distributions; and (2) establishing the diversity of planetary architectures and the frequency of planetesimal collisions as a function of time through observations of circumstellar debris disks. Together, these observations will provide an astronomical context for understanding whether our solar system - and its habitable planet - is a common or a rare circumstance. Achieving our science goals requires measuring precise spectral energy distributions for a statistically robust sample capable of revealing evolutionary trends and the diversity of system outcomes. Our targets have been selected from two carefully assembled databases of solar-like stars: (1) a sample located within 50 pc of the Sun spanning an age range from 100-3000 Myr for which a rich set of ancillary measurements (e.g. metallicity, stellar activity, kinematics) are available; and (2) a selection located between 15 and 180 pc and spanning ages from 3 to 100 Myr. For stars at these distances SIRTF is capable of detecting stellar photospheres with SNR >30 at λ≤24μ m for our entire sample, as well as achieving SNR >5 at the photospheric limit for over 50% of our sample at λ=70μ m. Thus we will provide a complete census of stars with excess emission down to the level produced by the dust in our present-day solar system. SIRTF observations obtained as part of this program will provide a rich Legacy for follow-up observations utilizing a variety of facilities including the VLT. More information concerning our program can be found at http://gould.as.arizona.edu/feps.