Radial velocity variations and line bisectors (V_span) of WASP-78 and WASP-79 folded on the best-fitting circular orbit periods (solid lines). The eccentric orbit solutions are shown as dashed-lines (see Sect. 6 for discussion). The bisector uncertainties of twice the RV uncertainties have been adopted. The mean values of the bisectors are indicated by the dotted lines. There is negligible correlation between V_span and orbital phase.