With this grant Drs. McAlister and Hartkopf at Georgia State University will continue a program of high angular resolution observations of binary star systems. Binary stars are the only source for the fundamental determination of stellar masses, and they can provide direct determinations of stellar distances, radii, luminosities, and temperatures. The Georgia State University (GSU) program of binary star of binary star speckle interferometry is the only such effort in the world routinely applying modern methods of high resolution imaging speckle techniques to these fundamental astrophysical problems. The GSU speckle group operates state-of- the-art data acquisition and analysis facilities and is routinely granted time on large telescopes at the U.S. national observatories and elsewhere. Speckle observations are being used to greatly improve the orbital elements of known binaries and to calculate the orbits of resolved spectroscopic systems and other newly discovered binaries. Techniques are also being developed and applied that enable the recovery of intensity and color information for the individual components of binary stars in a regime of angular separation heretofore inaccessible to existing methods.
