Related papers: BRITEning up the Be Phenomenon
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…
Empirical evidence for the involvement of nonradial pulsations (NRP's) in the mass loss from Be stars ranges from (i) a singular case (\object{$\mu$ Cen}) of repetitive mass ejections triggered by multi-mode beating to (ii) several…
Aims: From observations of the K4III star Beta UMi we attempt to determine whether oscillations or any other form of variability is present. Methods: A high-quality photometric time series of approximately 1000 days in length obtained from…
The analysis of the light curves of 48 B-type stars observed by Kepler is presented. Among these are 15 pulsating stars, all of which show low frequencies characteristic of SPB stars. Seven of these stars also show a few weak, isolated high…
The B0.5IVe star gam Cas is of great interest because it is the prototype of a small group of classical Be stars having hard X-ray emission of unknown origin. We discuss results from ongoing B and V observations of the gam Cas star-disk…
The expert system for time series analysis of irregularly spaced signals is reviewed. It consists of a number of complementary algorithms and programs, which may be effective for different types of variability. Obviously, for a pure sine…
Multiple oscillation frequencies separated by close to or less than the formal frequency resolution of a data set are a serious problem in the frequency analysis of time series data. We present a new and fully automated Bayesian approach…
Sensitivity of the frequencies of twenty two atomic transitions to the variation of the fine structure constant $\alpha$ is calculated. The findings are to be used in search for possible variation of $\alpha$ across our Galaxy using high…
13\,Tau is a rarely studied bright B9V type star ({\sl V} = 5.68 mag), which shows a weak and double-peaked H{$\alpha$} emission profile in its spectra. In this study, we presented high-precision photometric data of 13\,Tau taken by the…
Circumstances are described in which symmetry breaking during the formation of our three-dimensional brane within a higher-dimensional space in the early universe excites mesoscopic classical radion or brane-displacement degrees of freedom…
Abundances of beryllium in metal-poor stars scale linearly with metallicity down to [Fe/H] ~ -3.0. In the stars where Be has been detected at this extremely metal-poor regime, an increased abundance scatter has been previously reported.…
The frequency and properties of multiple star systems offer powerful tests of star formation models. Multiplicity surveys over the past decade have shown that binary properties vary strongly with mass, but the functional forms and the…
The aim of our observations is to investigate the intranight variability properties and the spectral variability of BL Lacertae. 799 optical multi-band observations were intensively made with the Beijing-Arizona-Taiwan-Connecticut (BATC)…
Observations of hot stars belonging to the young cluster SMC-NGC330 and its surrounding region were obtained with the VLT-GIRAFFE facilities in MEDUSA mode. We investigated the B and Be star properties and proportions in this environment of…
We investigate the particle-number fluctuations due to the collective excitations created in a two-dimensional (2D) and a quasi-2D Bose-Einstein condensates (BECs) at low temperature. We find that the fluctuations display an anomalous…
We determine which are the mechanisms accelerating the surface of single stars during the Main Sequence evolution. We have computed 112 stellar models of four different initial masses between 3 and 60 M_sun, at four different metallicities…
The massive (13,000-26,000 Msolar), young (15-30 Myr) Large Magellanic Cloud star cluster NGC 1818 reveals an unexpected increasing binary frequency with radius for F-type stars (1.3-2.2 Msolar). This is in contrast to many older star…
Boron provides a special probe below the stellar surface as it survives to greater depths than do Li and Be. To search for B depletions we have observed B in 13 F and G dwarfs with large Be depletions; for comparison we also obtained…
High-dispersion IUE data encode significant information about aggregate line absorptions that cannot be conveniently extracted from individual spectra. We apply a new technique in which fluxes from each echelle order of a short wavelength…
This study has three principal aims: (i) to increase the number of detected pulsation modes of 44 Tau, especially outside the previously known frequency ranges, (ii) to study the amplitude variability and its systematics, and (iii) to…