Bibcode
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
Journal
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.