Monthly notices of the royal astronomical society vol:333 issue:2 pages:L35-L39
We present spectroscopic and multicolour photometric evidence supporting the binary nature of the delta Scuti star XX Pyx (CD-24 7599). Applying a cross-correlation technique to the spectra, we find clear radial-velocity variations with a large amplitude. We derive the orbital parameters and confirm an orbital period of 1.15 d, as suggested previously on the basis of photometric variations. The amplitude of the slow variations present in our new multicolour data is wavelength independent, pointing also to a geometric effect as origin of the variability. They are thus fully consistent with the spectral variations and are interpreted as ellipsoidal variations. XX Pyx has a circular orbit of which the radial-velocity variations have a semi-amplitude of 17.8+/-0.4 km s(-1).