A photometric monitoring of bright high-amplitude δ Scuti stars

I. The double-mode pulsation of V567 Ophiuchi

¹ Department of Experimental Physics and Astronomical Observatory, University of Szeged, Dóm tér 9, Szeged 6720, Hungary
² Hungarian Eötvös Fellowship, Instituto de Astrofísica de Andalucía, CSIC, Granada, Spain
³ Department of Optics and Quantum Electronics, University of Szeged, POB 406, Szeged 6701, Hungary

Corresponding author: L. L. Kiss, l.kiss@physx.u-szeged.hu

Received: 12 July 2002
Accepted: 13 August 2002

Abstract

We present the first results of an observational project, which addresses the period changing behaviour of a sample of high-amplitude δ Scuti stars. In this paper we discuss the double-mode nature of V567 Ophiuchi. It was observed on 15 nights in two consecutive years in order to resolve the long-standing ambiguity related to its secondary period. A frequency analysis of almost 5000 individual single-filtered CCD V measurements resulted in two independent frequencies ( d^-1 and d^-1) with a ratio of . Earlier data taken from the literature were used to refine the dominant period, and the re-analysis supports the existence of the secondary period. Possible asteroseismological implications are briefly discussed.