The Space Interferometry Mission (SIM) will be a 10-m baseline optical interferometer in earth orbit. It will provide high-throughput astrometry with an estimated noise floor for bright stars of about 4 mu as over wide angles, and 1 mu as over small fields. This performance will allow accurate parallaxes and distances for a very large number of stars of different types throughout the Galaxy. Since it is a pointed rather than a scanning instrument, its astrometric performance can be maintained on objects as faint as 20th magnitude in the V band. SIM will address many areas of Galactic astronomy, including dynamics of stars in globular and open clusters, the Galactic halo, and spiral structure. It will perform rotational synthesis imaging with a resolution of 10 milliarcsec, allowing detailed study of stellar debris disks, young stellar objects, and AGN. SIM will perform a large survey of nearby stars for planetary systems, by detecting the astrometric wobble of the parent star. A Jupiter-mass planet signature will be measurable to 10% at a distance of 150 pc, and a Uranus-mass planet in a 1-AU orbit will be detectable to ~ 40 pc. Radial velocity programs are most sensitive to planets in orbits ≲ 1 AU, and are therefore complementary to SIM's survey for companions (including brown dwarfs) in wider orbits.
American Astronomical Society Meeting Abstracts #189
- Pub Date:
- January 1997