Analysis of a delta Scuti spectroscopic binary: CQ Lyncis

Abstract

CQ Lyn is a new double-lined spectroscopic binary, composed of an Am delta Scuti and a solar-like star, with an orbital period of 12.50736 d and a zero-eccentricity. Physical parameters of both stars are well constrained. The characteristics of the primary are the following: M=1.714 M_sun, T_eff=6760 K, log L/L_sun= 1.097 and log g=3.85 dex. Power spectra of HIPPARCOS photometry and CORAVEL radial velocities show multi-period pulsation behaviour. Three frequencies are identified: f₁=8.86725, f₂=8.81150 and f₃=8.91007 c/d and are assumed to be l=2 f-modes split by rotation, considering their pulsation constants Q₁=0.0356, Q₂= 0.0359 and Q₃=0.0355 d. Two combination oscillations are also present in the power spectrum at frequency f₁+f₂ and f₂+f₃. Based on observations collected at the 1.93-m and Swiss 1-m telescopes at the Haute-Provence Observatory (OHP, France), at the Belgian 1.2-m telescope at La Palma (ENO, Spain) and on data from the ESA HIPPARCOS satellite.