We obtained time-series high-resolution spectra of two beta Cephei stars (BW Vulpeculae and gamma Pegasi) covering several periods of their pulsation cycle. A total of 67 stellar spectra covering the wavelength range from 3531 to 7039 A with a spectral resolution of 30,000 is presented.
The Debrecen Photoheliographic Data (DPD) is a catalogue of daily positions and areas of sunspots compiled by using white-light full-disk observations taken at the Heliophysical Observatory (Debrecen, Hungary) and its Gyula Observing Station as well as at Kislovodsk (Russia). The present material is divided in two parts. The numerical part contains the measured data and the other part contains the CCD scans of all the active regions on the photographic plates.
Every measured spot is marked with the same number in the picture as in the numerical catalogue. The images along with the measured data allow more complex analyses, morphological studies and the comparison with magnetic, H alpha and other observations.
We present simultaneuos UBV and uvby photometry for the eighteen brightest northern Cepheids. Two fainter stars have been observed only through UBV filters in order to obtain the recent amplitude (V473 Lyr) and period (AW Per). The complete photometric database contains about 3500 individual measurements.
We have carried out high resolution (approx 1/40,000) optical spectroscopy in the red spectral region around H alpha for twelve Cepheids with UBV-uvby photometry, for the newly discovered classical Cepheid CK Cam and for two double-mode Cepheids (CO Aur and TU Cas). New cross-correlation radial velocities for fifteen Cepheids are presented with the observed normalized spectra for CO Aur and TU Cas.
As a result of a longer campaign of the investigation of Maia candidate stars running in the years 1992 to 1996, we present over 2200 radial-velocity values of 12 bright early-type stars of spectral type A2--B8 and luminousity class III--V. Radial velocities were measured on about 1000 photographic spectra and on about 1200 CCD spectra. Typical mean errors of the radial velocities from photographic spectra are 3 km/s for single lines and 0.6 km/s for all measured metal lines, and 0.6 km/s for the Si-doublet 6347/6371 A measured on the CCD spectra.
For the best studied star, gamma CrB, time series include data from single nights allowing for a time resolution down to 5 minutes, as well as groups of such series including several days, partly taken at two observing sites of different longitude. For the other stars, there are several time series within single nights scattered over the time interval from 1992 to 1995.
This publication contains a complete package of programs and data files representing a powerful tool for accurate and complete reductions of photoelectric observations, their reliable transformation into some standard photometric system, archiving and subsequent retrieval. It is especially suited for the reduction of Johnson UBV or Stromgren uvby observations but it can also be adapted to reduction of data obtained in other photometric systems which use 3 or 4 filters (data obtained in photometric systems using more than 4 filters would have to be reduced subsequently, in subsets of 3 or 4 filters). Reduction of observations obtained through only 1 or 2 filters are also possible, but possibilities of their reliable transformation into a standard system are somewhat limited by the very nature of the problem. The package has originally been published in JAD No.3 along with $UBV$ observations of Be stars secured over two decades at Hvar. Here, we re-publish it separately, in a slightly improved form.
Observations of variable stars offer a potential to test stellar structure and evolution. The observations can be either of single, isolated stars, or of variable stars in clusters. The STACC group (Frandsen 1992) has for the last several years searched for open clusters with a population of $\delta$~Scuti stars. To make this search more efficient, we have produced a target list with a number of promising open clusters. The list includes parameters, finding charts, Colour-Magnitude diagrams (CM diagrams) and references for the clusters. This target list is presented here, and is thus made available to observers interested in participating in the search for variable stars in open clusters.
In this paper we describe the motivation, contents and use of the STACC Open Cluster Target List. We also give some guidelines on how to make CCD observations of open clusters in order to search for variable stars.
We present 4314 $V$ magnitudes of the Mira variable chi Cygni obtained between the variable's discovery date in 1686 and the beginning of the present century. The estimates were made by 25 different observers, including Kirch (the discoverer of chi Cyg as a variable), Cassini, Halley, Olbers and Argelander. All magnitudes are given on the Johnson V scale. A consistent cycle-count scheme for the complete time interval is given.
In this paper we present more than 30,000 visual magnitude estimates of the Mira Variable chi Cygni, obtained by the members of the the BAA VSS (British Astronomical Association, Variable Star Section), VSOLJ (Variable Star Observing League Japan) and the VVS WVS (Vereniging voor Sterrenkunde, Werkgroep Veranderlijke Sterren, Belgium) from 1900 till 1998. The homogeneity and the accuracy of the data is discussed.
We present seven four-hour time series of high-resolution spectra of theta Tucanae, a double-lined binary delta Scuti star with an unusual mass ratio q=0.09. The spectra reveal line profile variations, and the radial velocity varies with K1=8.6 kms/s for the principal pulsation frequency f1=20.27 cycles per day.
VBLUW photometry (Walraven system) of 15 alpha Cyg--type variables, (luminous massive stars), including 10 LBVs and one suspected LBV are presented. Formulae are given to transform the V and V-B of the Walraven system to V and B-V of the Johnson UBV system.
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