2003A&A...407.1059R

We present the results of simultaneous uvbyβ photometry carried out from 1999 to 2001 of the variable V2109 Cyg together with a spectroscopic analysis based on one high resolution spectrum obtained in 2000. From this study, the star is definitively classified as an evolved δ Sct-type variable with solar metal abundances. This conclusion is also supported by the detected multiperiodic pulsational behaviour and the observed variation of the m₁ index over the pulsation cycle. This variation is slightly reversed relative to the V light curve, in very good agreement with the m₁ variation expected from the photometric calibrations. Besides the main frequency f₁=5.3745c/d and its first harmonic 2f₁, a secondary peak is found at f₂=5.8332c/d (f₁/f₂=0.92) with f₁ identified as a radial mode and f₂ as non-radial. Whereas no significant variations are found in the amplitude of f₁ from season to season, the amplitude of f₂ changes strongly. Moreover, the main period has remained constant since 1990, within the observational uncertainties. Additional secondary frequencies may also be excited in this variable.