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Precise Radial Velocities Of Giant Stars V. A Brown Dwarf And A Planet Orbiting The K Giant Stars Tau Geminorum And 91 Aquarii, David Mitchell

David Mitchell

Aims. We aim to detect and characterize substellar companions to K giant stars to further our knowledge of planet formation and

stellar evolution of intermediate-mass stars.

Methods. For more than a decade we have used Doppler spectroscopy to acquire high-precision radial velocity measurements of

K giant stars. All data for this survey were taken at Lick Observatory. Our survey includes 373 G and K giants. Radial velocity data

showing periodic variations were fitted with Keplerian orbits using a χ2 minimization technique.

Results. We report the presence of two substellar companions to the K giant stars τ Gem and 91 Aqr. …