Related papers: BRITEning up the Be Phenomenon
We have determined beryllium abundances for 25 metal-poor stars based on the high resolution and high signal-to-noise ratio spectra from the VLT/UVES database. Our results confirm that Be abundances increase with Fe, supporting the global…
Atomic diffraction through double slits and transmission gratings is well described in terms of the associated de Broglie waves and classical wave optics. However, for weakly bound and relatively large systems, such as the He_2 dimer, this…
The number ratios Be/(B+Be) of Be to B-type stars in young, well studied clusters of the Galaxy, the LMC and SMC are examined. In order to disentangle age and metallicity effects we choose clusters in the same age interval and for which…
Light curves of the contact systems visible in the direction of Baade's Window have been analyzed using the first coefficients of the Fourier representation. The results confirm that the geometric contact between components is usually weak.…
The study of Be in stars of differing metal content can elucidate the formation mechanisms and the Galactic chemical evolution of Be. We have obtained high-resolution, high signal-to-noise spectra of the resonance lines of Be II in eight…
$\nu$ Eridani is a well known multiperiodic $\beta$ Cephei pulsator which exhibits also the SPB (Slowly Pulsating B-type stars) type modes. Recent frequency analysis of the BRITE photometry of $\alpha$ Lupi showed that the star is also a…
We present high-quality spectra of the majority of stars that have been classified as Oe and find that their published spectral types are generally too early, most likely due to infilling of HeI lines. As a matter of fact, all stars…
An extensive beryllium abundance analysis was conducted for 118 solar analogs (along with 87 FGK standard stars) by applying the spectrum synthesis technique to the near-UV region comprising the Be II line at 3131.066 A, in an attempt to…
Many astronomical phenomena, including Fast Radio Bursts and Soft Gamma Repeaters, consist of brief, separated, seemingly aperiodic events. The intervals between these events vary randomly, but there are epochs of greater activity, with…
A sample of 97 galactic field Be stars were studied by taking into account the effects induced by the fast rotation on their fundamental parameters. All program stars were observed in the BCD spectrophotometric system in order to minimize…
The overall frequency and other statistical properties of binary systems suggest that star formation is intrinsically a complex and chaotic process, and that most binaries and single stars actually originate from the decay of multiple…
A reliable determination of the basic physical properties and variability patterns of hot emission-line stars is important for understanding the Be phenomenon and ultimately, the evolutionary stage of Be stars. This study is devoted to one…
We present a detailed lightcurve analysis for a sample of bright semiregular variables based on long-term (70--90 years) visual magnitude estimates carried out by amateur astronomers. Fundamental changes of the physical state (amplitude…
In this paper, we used the database of the university of Michigan Radio Astronomy Observatory (UMRAO) at three (4.8 GHz, 8.0 GHZ, and 14.5 GHz) radio frequency to analyze the radio light curves by the power spectral analysis method in…
We present new UVES spectra of a sample of 15 cool unevolved stars with and without detected planetary companions. Together with previous determinations, we study Be depletion and possible differences in Be abundances between both groups of…
We analysed 337 multi-epoch optical spectra of 38 Herbig Ae/Be (HAeBe) stars to gain insights into the variability behaviour of the circumstellar (CS) atomic gas. Equivalent widths (EWs) and line fluxes of the Halpha, [OI]6300, HeI5876 and…
Variability of a galaxy's core radio source can be a significant consequence of AGN accretion. However, this variability has not been well studied, particularly at high radio frequencies. As such, we report on a campaign monitoring the high…
We show that the four-wave mixing can restrict spectral broadening. This is a general physical phenomenon that occurs in one-dimensional systems of four wave packets that resonantly interact "2-to-2": $…
We consider the high radio frequency (15 GHz - 353 GHz) properties and variability of 35 Brightest Cluster Galaxies (BCGs). These are the most core-dominated sources drawn from a parent sample of more than 700 X-ray selected clusters, thus…
Magnetic B-type stars exhibit photometric variability due to diverse causes, and consequently on a variety of timescales. In this paper we describe interpretation of BRITE photometry and related ground-based observations of 4 magnetic…