A search for delta Scuti stars in northern open clusters. I. CCD photometry of NGC 7245, NGC 7062, NGC 7226 and NGC 7654

Viskum, M.; Hernandez, M. M.; Belmonte, J. A.; Frandsen, S.
Bibliographical reference

Astronomy and Astrophysics, v.328, p.158-166 (1997)

Advertised on:
12
1997
Number of authors
4
IAC number of authors
2
Citations
26
Refereed citations
22
Description
In an effort to test stellar structure and evolution models, analysis of oscillations in A and F stars in open clusters is carried out by the STACC network (Frandsen cite{stacc}). In this paper we describe our effort to locate a suitable open cluster in the northern hemisphere for a future multi-site campaign. We present BV Johnson and time series CCD photometry of four poorly studied open clusters: NGC 7245, NGC 7062, NGC 7226 and NGC 7654. New improved colour-magnitude diagrams for these four northern hemisphere clusters, together with the results from the search for variable stars in the clusters are presented. The cluster reddening, distance and age are estimated from isochrone fitting. In the four clusters, we discovered a total of two delta Scuti stars, one eclipsing binary, one variable of unknown type and evidence for 3 potential variables all situated within the delta Scuti instability strip. We find that the fraction of delta Scuti stars in these four open clusters is much lower than among field stars and in other open clusters suggesting that some additional parameters control the pulsation, parameters that we do not understand at this moment.
Type