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B-type pulsators in the central region of NGC 869 (h Persei)
J. Krzesiski 1,2,
A. Pigulski 3 and
Z. Kolaczkowski 3
Received 21 December 1998 / Accepted 4 February 1999
In the course of the search for B-type pulsators in the central region of h Persei, we discovered two Cephei stars, Oo 692 1 and Oo 992, and one SPB star, Oo 893. The first two stars are monoperiodic pulsators with periods of 0.1716946 and 0.1326359 d respectively, and semi-amplitudes smaller than 0.01 mag. The light curve of Oo 893 can be described by a single 1.193633-day period, slightly non-sinusoidal in shape, and having semi-amplitudes from 19 mmag in to 48 mmag in U. Oo 893 is the first SPB star found in h and Persei.
In addition, we discovered seven other variables, including three eclipsing binaries and one Eri star. One of the binaries is a W UMa-type star and a likely cluster member.
We also present new UBV photometry for 258 stars in the field. The average reddening, estimated from the cluster colour-colour diagram, amounts to = 0.52 mag. A 0.1 mag dispersion of reddenings within the cluster is also seen.
Key words: stars: binaries: eclipsing stars: oscillations stars: variables: general Galaxy: open clusters and associations: individual: NGC 869 = h Per
Send offprint requests to: A. Pigulski
Online publication: April 19, 1999