Published online by Cambridge University Press: 15 February 2011
By fitting the revised Hipparcos intermediate astrometric data (HIAD), we obtain thephotocentric orbital solutions of some single-lined spectroscopic binaries (SB1s) in the9th Catalogue of Orbits of Spectroscopic Binaries (SB9). For SB1s with relatively smallmagnitude difference between the two components, we find that the primary orbit is not agood approximation of the photocentric orbit in their orbit determination and suggest thatfuture spectroscopic observations and advanced spectral separation techniques should beapplied to these systems. In order to facilitate these future observations, we alsoestimate the full orbital solutions and provide the observational ephemerides. As anexample, we give the result for HIP 113860.