  It has long been speculated that the observed periodic radial velocity
pattern for the K giant Pollux might be explained in terms of an orbiting
planetary companion. We have collected 80 high-resolution spectra for Pollux at
Lick Observatory yielding precise radial velocities with a mean error of 3.8
m/s, providing the most comprehensive and precise data set available for this
star. Our data confirm the periodicity previously seen in the radial
velocities. We derive a period of 589.7+/-3.5 days and, assuming a primary mass
of 1.86 M_Sun, a minimum companion mass of 2.9+/-0.3 M_Jup, consistent with
earlier determinations. No evidence for any periodicities is visible in our
analysis of the shapes of the spectral lines via the bisector method, so that
we conclude that evidence is accumulating and compelling for a planet around
Pollux. However, some last doubt remains about this interpretation, because
non-radial pulsations which might be present in giant stars could in principle
also explain the observed radial velocities, while the accompanying bisector
variations might be too small to be detectable with current data.
