視線速度
Radial velocity variations of Theta Cygni have been detected by the ELODIE team while searching of extrasolar planets. Desort et al. (2009) infer these variations are not caused by a dim stellar companion roughly 80 Astronomical Units away from the star, but suggest instead the presence of a perturbing planetary object, twice as massive as Jupiter and orbiting around the primary star in roughly 150 days. This extrasolar planet has yet to be confirmed. Observations made at Lick Observatory show evidence for radial velocity variation at this period as well as at yearly aliases, however these signals have not reached statistical significance.