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Pulsating Stars in the ASAS-3 Database. I. β Cephei Stars

Piguslki A.

Acta Astronomica

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2005

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Vol. 55, No. 2

219--236

EN

We present results of an analysis of the ASAS-3 data for short-period variables from the recently published catalog of over 38 000 stars. Using the data available in the literature we verify the results of the automatic classification related to β Cep pulsators. In particular, we find that 14 stars in the catalog can be classified unambiguously as new β Cep stars. By means of periodogram analysis we derive the frequencies and amplitudes of the excited modes. The main modes in the new β Cep stars have large semi-amplitudes, between 35 and 80 mmag. Up to four modes were found in some stars. Two (maybe three) new β Cep stars are members of southern young open clusters: ASAS 164409-4719.1 belongs to NGC 6200, ASAS 164630-4701.2 is a member of Hogg 22, and ASAS 164939-4431.7 could be a member of NGC 6216. We also analyze the photometry of four known β Cep stars in the ASAS-3 catalog, namely IL Vel, NSV 24078, V1449 Aql and SY Equ. Finally, we discuss the distribution of β Cep stars in the Galaxy.

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Variable Stars in the Old Open Cluster Berkeley 39

Mazur B., Krzemiński W., Kaluzny J.

Acta Astronomica

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1999

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Vol. 49, No. 4

551--560

EN

We present the results of a CCD photometric survey of the old open cluster Berkeley 39. We discovered 5 new variables, one of which is a W UMa-type system, one is probable δ Scuti pulsating blue straggler, and three are stars for which the eclipse-like events were observed - most likely they are detached binaries. V-band light curves of the previously identified binaries, as well as the improved periods and colors at maximum are given.

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Stellar Variability Background in OGLE-I Microlensing Search

Woźniak P., Szymański M.

Acta Astronomica

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1998

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Vol. 48, No. 2

269--288

EN

We search OGLE-I photometric database for stars which, as defined by formal criteria adopted by OGLE-I microlensing search, showed variability during only one out of 3 or 4 observing seasons. The results include 17 previously reported microlensing events, 2 newly discovered candidate events and 15 intrinsically variable stars that have a potential of contaminating samples of microlensing events. Based on photometry obtained in 1992 and 1993 OGLE #10 was tentatively included in the list of microlensing candidates, however its light curve in 1994 and 1995 shows many characteristics of the variable stars found in our search, and most likely it is not a microlensing event. For all stars which passed our tests, we provide 44×44 arcsec (101×101 pixel) centered subframes from each OGLE-I frame in the I-band. It is the first time when images used to derive photometry of microlensing events are available in convenient format to astronomical community.

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Search for Long-Period and Non-Periodic Variable Stars in the OGLE-I Databases

Żebruń K.

Acta Astronomica

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1998

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Vol. 48, No. 2

289--329

EN

We present a list of long-period and non-periodic variable stars detected in the OGLE-I databases. These stars were not included in previous catalogs of periodic stars found in OGLE data. The catalog contains 116 stars in twelve Baade's Window fields and additionally in the Galactic bulge fields: MM1/5/7-A/B, MM3 and GB1. The catalog and individual observations are available in digital form from the OGLE Internet archive.

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Fourier Coefficients of OGLE Variables. I. Parameters for the Baade's Window, MM5-A, MM5-B, MM7-A, and MM7-B Field Variables

Morgan S. M., Simet M., Bargenquast S.

Acta Astronomica

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1998

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Vol. 48, No. 2

331--339

EN

Fourier coefficients for the variable stars in the OGLE survey of the Galactic center were derived. In most cases the classification of the variable type is confirmed but there are some cases where the classification is brought into question. The Fourier coefficients for all of the variables including RR Lyraes, δ Scuti and SX Phe stars, as well as an Anomalous Cepheid are presented. In general the distribution of the Fourier coefficients for the different types of variable stars in this study lie within the observed ranges of other studies.