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R.L. Swartz (JPL)
SIM-Planetquest relies on a grid of 1302 stars covering the sky to determine instrument parameters such as baseline length, orientation, and other calibration values. It is necessary that these stars be well-understood to 4 microarcseconds astrometric precision. While pre-mission ground observations attempt to eliminate stars with complex behavior from the grid, we still expect 60% of the final grid stars to have companions. If not corrected for this effect, the companions will render the grid insufficient. This study shows that we can create a usable grid by detecting and compensating for these complex motions by use of delay residuals and adding acceleration terms to the stellar parameters.
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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.