Contribution a l'etude des spectres composites. VI. HD 66068-9.

HD 66068-9 is listed by Hynek (1938) as a star having a composite spectrum. Classifications made by various authors and by us indicate that this star is, in fact, an Am one. Our radial velocity observations, carried out at the Observatoire de Haute-Provence with the spectrovelocimeter CORAVEL, show HD 66068-9 to be a double-lined spectroscopic binary with the following orbital elements: P=7.74799days; T=2447600.690JD; ω=341.1deg; e=0.418; K_1_=56.1km/s; K_2_=75.1km/s; V_0_=-21.1km/s; a_1_sini=5.43x10^6^km; a_2_sini=7.27x10^6^km; M_1_sin^3^i=0.78M_sun_; M_2_sin^3^i=0.58M_sun_. The system appears to be a detached one (a=~25R_sun_) without possibility of eclipses (i=~47deg); the secondary component should be an early F dwarf star. The ratio of the corelation dip areas indicates a blue magnitude difference {DELTA}m~1.6mag., and the dip area of the primary alone a metallicity [Fe/H]=~0.37dex for the Am star. Rotation-revolution synchronism is discussed: we conclude that this binary does not rotate synchronically but perhaps that pseudo-synchronization occurs near the periastron passage, according to Hut's theory. Perturbations of some radial velocities during 1983 suggest the existence of a long period third body.