This grant will support the use of the high precision radial velocity spectrometer at the E.W. Fick Observatory in Iowa to continue and complete three projects involving radial velocity measurements of F, G, and K type stars: (1) Monitoring of radial velocity variations for a list of binary star systems with orbital periods between 1 and 20 years; (2) a distance-limited sample of all F, G, and early K stars within 25 parsecs of the Sun; and (3) a survey complete to 9th magnitude in a band around 30 degrees declination. High precision radial velocity measurements are needed (a) to improve our knowledge of the frequency of binarity among stars; (b) to determine the orbital parameters of binary stars which leads to improved determinations of the stellar masses; and (c) for use in stellar motion studies, including the distances of nearby clusters, the determination of membership in clusters or moving groups, verification of wide binary pairs, improved determination of the solar motion and the local standard of rest, and statistical parallaxes. Since major projects underway elsewhere are expected to yield high precision astrometric data over the next five years, the collection of new, high precision radial velocities is both necessary and timely.
