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W. G. Bagnuolo, S. F. Taylor, H. A. McAlister, T. ten Brummelaar, L. Sturmann, J. Sturmann, N. H. Turner, D. Berger (Georgia State University), S. T. Ridgway (KPNO, NOAO), Center for High Angular Resolution Astronomy (CHARA) Collaboration
Individually resolved packets are produced by scans from the CHARA Interferometer Array for binary stars with separations from 10 to 100 milli-arcsec (mas) in the K' band. We have used this data for astrometry of the binary with the goal of improving the visual orbits for these systems. About 12 data sets of 400 scans each can be collected for a star within an hour. The intrinsic accuracy with simple linear/quadratic fits to the time-separation curve yields accuracies of 0.15 mas. But, for systems with separations less than 80 mas, the measured separation is modulated periodically by the secondary star's packet riding over the sidelobes of the primary which provides a phase reference. This "sidelobe verniering" can improve the precision to better than 50 micro-arcsec. These techniques, represents 1-2 orders of magnitude improvement in astrometic accuracy over speckle interferometry techniques. Visual orbits can then be refined via a maximum liklihood technique, which leads to revisions in the stellar masses. We present the results for several binaries that have been observed at the CHARA Array, starting in 2001.
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The author(s) of this abstract have provided an email address for comments about the abstract: bagnuolo@chara.gsu.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.