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Session 12 - Binary Stars.
Display session, Monday, June 08
Atlas Ballroom,

[12.15] Scanning the Fringe Pattern of a Long Baseline Interferometer to Detect Non-singularity and to Measure the Angular Separation and Relative Brightness of the Components of a Binary Star System

J. Hershey, E. Nelan (STScI), O. Franz, L. Wasserman (Lowell Observatory)

Long Baseline Interferometers offer angular resolution unachievable by any other means. By scanning the fringe pattern, rather then only tracking it, additional angular resolution of binary star systems, and hence additional information about them, can be obtained. This can be achieved by reconstructing the entire fringe pattern from a binary system along an appropriate length of the delay line, and therefore over some angle on the sky, and deconvolvng the observed multi-source fringe pattern with reference patterns of point sources of appropriate spectral colors. This technique will provide information about the projected angular separation of the binary's components as well as thier relative brightness. If the delay line scan is sufficiently long, then wide binaries with large magnitude differences will be detected. If the separation is closer than the charactistic angular distance between the "sine wave" fringes, the deconvolution technique will "resolve" the components as well. In both of these cases, simple monitoring of the fringe visibility or amplitude may have failed to detect the non-singularity of the object. Furthermore, we demonstrate that there exists a family of binary parameters (magnitude differences and angular separations) that result in nearly identical fringe amplitudes but are easily distinguished, and hence solved for, by the details of the fringe morphologies. This observing technique has been successfully employed by HST's Fine Guidence Sensors and can be used by both space based and ground based interferometers to detect and study binary star systems.

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