The Final Report: Detecting Terrestrial Mass Planets Around M-dwarfs: Is SIM's performance competitive?

Here, we present our final report on our SIM Science Study to determine the effect of intrinsic stellar jitter on our ability to detect terrestrial planets around low-mass stars with micro-arcsecond astrometry. The study has had two primary goals: 1) To assess the astrophysical limits of ultra-precision astrometric measurements of M-dwarfs compared to those of other detection methods and 2) To assess the scientific impact of an M-dwarf SIM GO survey to look for terrestrial planets. To achieve these goals, we had completed the task of designing a SIM GO target sample that considered the strengths and weaknesses of making optical astrometric measurements of M dwarfs. We have also analyzed now public CoRoT photometry of a sub-sample of M dwarfs to look for periodic signals and large photometric dispersions on data which has been corrected for problematic systematic issues. This analysis will result in an estimate of the photometric variation of M dwarfs as a function of spectral type. We used this photometry to determine the effect of difference sources of intrinsic jitter on astrometric and radial velocity measurements through realistic jitter models. This lead to an estimate of the expected yield of the GO program through Monte Carlo models that utilize the info gained from the jitter models. Finally, we compared these results to a reasonably designed radial velocity survey of the same targets.