Analytic Study of Grid Star and Reference Star Selection for the Space Interferometry Mission

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Title: Analytic Study of Grid Star and Reference Star Selection for the Space Interferometry Mission
Creators: Gould, Andrew
Issue Date: 2001-09-20
Publisher: American Astronomical Society
Citation: Andrew Gould, "Analytic Study of Grid Star and Reference Star Selection for the Space Interferometry Mission," The Astrophysical Journal 559, no. 1 (2001), doi:10.1086/322334
DOI: 10.1086/322334
Abstract: Grid stars and reference stars provide the fundamental global and local astrometric reference frames for observations by the Space Interferometry Mission. They must therefore be astrometrically stable at the ~1 μas level. I present simple formulae in closed form to estimate the contamination of these frames by motions due to stellar companions that go undetected in a radial-velocity (RV) survey of specified precision. The contamination rate depends almost entirely on the binary-period distribution function and not on the details of the mass or eccentricity distributions. Screening by a modest RV survey (σ_RV = 60 m s^-1) can reduce the fraction of grid stars with detectable unmodeled accelerations to <<1%. Reference-star selection promises to be much more challenging, partly because the requirements of astrometric stability are more severe and partly because the required density of sources is ~100 times higher, the latter of which implies that less satisfactory candidates will have to be accepted. The tools presented here can help design a reference-star selection strategy, but a full treatment of the problem will require better knowledge of their companions in the planetary mass range.
ISSN: 1538-4357
URI: http://hdl.handle.net/1811/47872
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