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

Abstract

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 best-fitting 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 5.350 4751 ± 0.000 0006 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 -1, and it appears that 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. © 2007 The Authors.