The first high-amplitude delta Scuti star in an eclipsing binary system

We report the discovery of the first high-amplitude δ Scuti star in an eclipsing binary, which we have designated UNSW-V-500. The system is an Algol-type semi-detached eclipsing binary of maximum brightness V = 12.52 mag. A bestfitting solution to the binary light curve and two radial velocity curves is derived using the Wilson-Devinney code. We identify a late A spectral type primary component of mass 1.49±0.02 M⊙ and a late K spectral type secondary of mass 0.33± 0.02 M⊙, with an inclination of 86.5± 1.0 , and a period of 5.3504751± 0.0000006 d. A Fourier analysis of the residuals from this solution is performed using PERIOD04 to investigate the δ Scuti pulsations. We detect a single pulsation frequency of f1 = 13.621± 0.015 cd , and it appears this is the first overtone radial mode frequency. This system provides the first opportunity to measure the dynamical mass for a star of this variable type; previously, masses have been derived from stellar evolution and pulsation models.