Related papers: Variability of Be Stars in Southern Open Clusters
In order to understand the formation mechanism of the disks around Be stars it is imperative to have a good overview of both the differences and similarities between normal B stars and the Be stars. Here we investigate a previous report…
In this work, we have studied the variable stars in the young open cluster NGC 1893 based on a multi-year photometric survey covering a sky area around the cluster up to $31' \times 31'$ wide. More than 23\,000 images in the $V$ band taken…
Relative proper motions and cluster membership probabilities have been derived for ~ 2500 stars in the field of the open star cluster NGC 3766. The cluster has been observed in $B$ and $V$ broadband filters at two epochs separated by ~ 6…
As Be stars are restricted to luminosity classes III-V, but early B-type stars are believed to evolve into supergiants, it is to be expected that the Be phenomenon disappears at some point in the evolution of a moderately massive star,…
Aims. The X-shooter archive of several thousand telluric star spectra was skimmed for Be and Be-shell stars to derive the stellar fundamental parameters and statistical properties, in particular for the less investigated late type Be stars,…
We report the discovery of 19 variable stars and two blue-stragglers in the field of the open cluster NGC6866. Three of the variable stars we classify as delta Sct, two, as gamma Dor, four, as WUMa, two, as ellipsoidal variables, and one,…
In this study, we analyze the emission lines of different species present in 118 Galactic field classical Be stars in the wavelength range of 3800 - 9000 \AA. We re-estimated the extinction parameter (A$_V$) for our sample stars using the…
We present a study of the abundance of Be stars in open clusters as a function of the cluster age, using whenever possible ages determined through Stromgren uvby photometry. For the first time in studies of this kind we have considered…
(Abridged version) We present the first detailed imaging polarization observations of six SMC and six LMC clusters, known to have large populations of B-type stars which exhibit excess H-alpha emission, to constrain the evolutionary status…
This paper checks on the roles of metallicity and evolutionary age in the appearance of the so-called Be phenomenon. Slitless CCD spectra were obtained covering the bulk of the Small Magellanic Cloud. For Halpha line emission twice as…
Be stars are rapid rotators surrounded by a gaseous disk envelope whose origin is still under debate. This envelope is responsible for observed emission lines and large infrared excess. To progress in the understanding of the physical…
This paper reports the discovery of new slowly pulsating B-type stars. Based on the photometric, spectral, and astrometric data of TESS, LAMOST, and Gaia surveys, we have found 286 new slowly pulsating B-type stars (SPB stars) and 21…
We present the results of a photometric survey for Be stars in eleven young clusters in the Large Magellanic Cloud and fourteen young clusters in the Small Magellanic Cloud. B stars with hydrogen in emission are identified on the basis of…
Combination of high-precision photometry and spectroscopy allows the detailed study of the upper main sequence in open clusters. We are carrying out a comprehensive study of a number of clusters containing Be stars in order to evaluate the…
NGC 7419 is a young open cluster notable for hosting five Red Supergiants and a high abundance of Classical Be (CBe) stars. CBe stars are main sequence non-supergiant B-type stars, which exhibit or have exhibited Balmer line emissions in…
Determinations of beryllium abundance in stars, together with lithium, provide a key tool to investigate the so far poorly understood extra-mixing processes at work in stellar interiors. We measured Be in three open clusters,complementing…
We present an analysis of high-resolution optical spectra recorded for 30 stars of the split extended main-sequence turnoff (eMSTO) of the young ($\sim$ 40 Myr) Small Magellanic Cloud (SMC) globular cluster NGC 330. Spectra were obtained…
Be stars are widely considered to be the product of binary interaction. However, whether all Be stars are formed via binary interaction is unclear, and detailed estimates of the multiplicity of Be stars and characterization of their…
A photometric study of variable stars in the field of old open cluster NGC 188 is discussed. Observations were carried out in two bands R and I for 5513 stars up to R = 17 mag in the field of 1.5 x 1.5 grad. around the cluster. The…
The recent variability survey of the NGC 3766 cluster revealed a considerable number of periodic variable stars in a region of the H-R diagram where no pulsation is expected. This region lies between the instability strips of the delta…