Physics and Astronomy Calendar

The early proper motion surveys conducted by Willem Luyten discovered thousands of so-called common proper motion binary stars. Such loosely bound pairs have separations ranging up to ~0.1 parsecs, implying extremely long orbital periods and no significant interaction between components. In many ways such "fragile binaries" are like open clusters with only two components of the same age. They provide a largely overlooked avenue for the investigation of many astrophysical questions. For example, the orbital distribution of fragile binaries with two long-lived main sequence components provides limits on the cumulative effects of the Galactic environment. In pairs where one component is evolved, the orbits have been amplified by post-main-sequence mass loss, potentially providing useful constraints on the initial-to-final mass relation for white dwarfs. In addition, the cooling ages of white dwarf components provide useful limits on the ages of their main sequence companions, independent of other stellar age determination methods. This talk will summarize how fragile binaries provide useful leverage on these and other problems of astrophysical interest.