DDA 33rd Meeting, Mt. Hood, OR, April 2002
Session 7. Posters
Monday, April 22, 2002, 7:00pm

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[7.06] Investigations into the Nature of the Multiple System Finsen 332: Tweedledee and Tweedledum

B.D. Mason, W.I. Hartkopf (U.S. Naval Observatory)

Two of the most challenging objects for optical interferometry in the middle of the last century were the two close components (FIN 332) of the wide visual binary STF2375 (= WDS 18455+0530 = HIP 92027 = ADS 11640). Each component of the wide pair was found to have subcomponents of approximately the same magnitude, position angle and separation and, hence, were designated by the tongue in cheek monikers ``Tweedledum and Tweedledee'' by the great visual interferometrist William S. Finsen in 1953. They were later included in a list of ``Double Stars that Vex the Observer'' by W.H. van den Bos in 1958.

While speckle interferometry has reaped a rich harvest investigating the close inteferometric binaries of Finsen, the ``Tweedles,'' have continued to both fascinate and exasperate due to both the great similarity of the close pairs as well as the inherent 180\circ ambiguity associated with interferometry. Both of these have led to numerous difficulties.

Detailed analysis of all published observations of the system have revealed several errors which are here corrected, allowing for presentation of these preliminary orbital elements, which are a powerful aid in resolving identification or quadrant equivocality. A unique software filter is being developed which will allow subarrays from crucial archival ICCD speckle data from 1982 to be re-reduced. Those data, combined with new observations obtained in 2001 from NOAO 4-m telescopes, as well as high quality unresolved measures should all allow for marked improvement in these orbital elements.

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Bulletin of the American Astronomical Society, 34, #3
© 2002. The American Astronomical Society.