  Recently Gatewood, Han & Black presented an analysis of the Hipparcos stellar
positions and their own ground-based measurements of rho CrB, suggesting an
astrometric orbit of 1.5 mas with an extremely small orbital inclination of 0.5
degrees. This indicates that the planet-candidate secondary might be a late M
star. We used the Hipparcos data of rho CrB together with the individual radial
velocities of Noyes et al. to independently study the stellar orbit and to
assess its statistical significance. Our analysis yielded the same astrometric
orbit. However, a permutation test we performed on the Hipparcos measurements
indicated that the statistical significance of the astrometric orbit is only
2-sigma. Therefore, we can expect about one out of 40 systems with a similar
data set to show a false astrometric orbit.
