The SIM planet search program consists of three main scientific areas:

• Deep search. One of the most important planet programs is a search for terrestrial planets around the nearest ~250 stars. Because this program is the most demanding in terms of astrometric accuracy, it is termed the "Deep Search." It will use the full capability of SIM to make 1 uas accurate measurements.

• Broad survey. A second planet search program called the "broad survey" is aimed at lower accuracy ~ 3uas but a much larger ~2000 star sample. The goal of this program is to explore the prevalence of Neptune and larger mass planets in all stellar types in our part of the Galaxy.

• Planets around young stars. The third component of the SIM planet search program is the search for Jupiter mass planets around young stars. To date more than 100 planets have been discovered outside our solar system. The vast majority of these planetary systems are very different from our own solar system. In particular the discovery of 'Hot Jupiters' has led to a variety of theories on how such planets are formed. The search for planets around young stars is aimed at studying planetary systems with one or more Jupiter mass planets before the system has reached a long term equilibrium.

SIM Science Investigations