delta Scuti-type nature of the variable V2109 Cyg

Description

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 m 1 index over the pulsation cycle. This variation is slightly reversed relative to the V light curve, in very good agreement with the m 1 variation expected from the photometric calibrations. Besides the main frequency f 1 = 5.3745 cd −1 and its first harmonic 2 f 1 , a secondary peak is found at f 2 = 5.8332 cd −1 (f 1 / f 2 = 0.92) with f 1 identified as a radial mode and f 2 as non-radial. Whereas no significant variations are found in the amplitude of f 1 from season to season, the amplitude of f 2 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.

Abstract

Astronomy and Astrophysics, v. 407, p. 1059-1065, 2003. http://dx.doi.org/10.1051/0004-6361:20030925

Abstract

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