SIMBAD references

A series of 35 high-resolution spectra are used to measure the third-signature plot of the G8 III star, ζ Cygni, which shows convective velocities only 8% larger than the Sun. Bisector mapping yields a flux deficit, a measure of granulation contrast, typical of other giants. The observations also give radial velocities with errors ∼30 m/s and allow the orbit to be refined. Velocity excursions relative to the smooth orbital motion, possibly from the granulation, have values exceeding 200 m/s. Temperature variations were looked for using line-depth ratios, but none were found.