LONG, ACCURATE TIME-SERIES MEASUREMENTS OF RADIAL-VELOCITIES OF SOLAR-TYPE STARS

We have been measuring changes in the radial velocities (RV's) of sola r-type stars to search for gravitational perturbations by planets. We transmit violet starlight through a Fabry-Perot etalon interferometer and sense changes in Doppler shift from changes in the fluxes of light on the slopes of stellar absorption lines. Our data now span 6 years. Our observations of the Sun showed earlier that both our technique an d the profiles of solar photospheric violet absorption lines can be st able enough to reveal planetary perturbations. We now carry this valid ation to the spectra of other near-solar-type stars. Annual averages o f our RV's of sigma Draconis and beta Virginis are stable to +/-6 m s- 1. The slope of our five-year series of RV's of xi Bootis A is consist ent with the star's well-determined visual astrometric orbit about xi Bootis B. The Fabry-Perot technique of Doppler shift measurement is fu lly capable of detecting perturbations due to planets with masses and orbits similar to those of Jupiter.