Binary Stars

As a class, binary stars are ideally suited to speckle inter-
ferometry. Suitable candidates for measurement exist in
almost unlimited supply, and speckle methods are provid-
ing hundreds of new discoveries while measuring previ-
ously known systems with greatly enhanced accuracy over
classical methods. There currently exist more than 30,000
speckle measurements of some 4000 binary star systems,
many of which have been measured through sufficient
orbital motions to permit calculation of the parameters
describing these motions. Approximately 10% of these
systems had not been previously resolved. These orbital el-
ements lead to the determination of the masses of the com-
ponents, quantities that can then be used to confirm or im-
proved theoretical models of stellar structure, formation,
and evolution. In addition to its high-resolution capability,
speckle interferometry allows the measurement of known
binary stars with an order-of-magnitude increase in accur-
acy in comparison with classical techniques. This ul-
timately leads to an increase in the accuracy of mass
determinations.
Because of the increased resolution of speckle inter-
ferometry over other methods, speckle surveys for new
binaries are able to penetrate into separation regimes not
previously detectable. These surveys, although rather lim-
ited in extent because of the strong competition for time
on the largest telescopes, are supporting already existing
evidence that the majority of stars in our galaxy exist in
binary or multiple star systems of higher complexity.