Related papers: A Parameter Study of Classical Be Star Disk Models…
Emission lines formed in decretion disks of Be stars often undergo long-term cyclic variations, especially in the violet-to-red (V/R) ratio of their primary components. From observations of the bright Be-shell star zeta Tau, the possibly…
Among the known groups of pulsating stars, $\delta$ Sct stars are one of the least understood. Theoretical models do not predict the oscillation frequencies that observations reveal. Complete asteroseismic studies are necessary to improve…
Massive stars are important building blocks of the Universe, and their stellar structure and evolution models are fundamental cornerstones of various fields in modern astrophysics. The precision of these models is limited by our lack of…
We study the characteristics of the outflow in disks of Be stars, based on the viscous decretion disk scenario. In this scenario, the matter ejected from the equatorial surface of the star drifts outward because of the effect of viscosity,…
Variability is a commonly observed property of classical Be stars (CBe) stars. In extreme cases, complete disappearance of the H{\alpha} emission line occurs, indicating a disc-less state in CBe stars. The disc-loss and reappearing phases…
Stellar population synthesis (SPS) models are used to infer many galactic properties including star formation histories, metallicities, and stellar and dust masses. However, most SPS models neglect the effect of circumstellar dust shells…
The circumstellar disk density distributions for a sample of 63 Be southern stars from the BeSOS survey were found by modelling their H$\alpha$ emission line profiles. These disk densities were used to compute disk masses and disk angular…
We present optical $WBVR$ and infrared $JHKL$ photometric observations of the Be binary system $\delta$ Sco, obtained in 2000--2005, mid-infrared (10 and $18 \mu$m) photometry and optical ($\lambda\lambda$ 3200--10500 \AA)…
In the last decade, the viscous decretion disk model has emerged as the new paradigm for Be star disks. In this contribution, we propose a simple analytical model to estimate the continuum infrared excess arising from these circumstellar…
The viscous decretion disk (VDD) model is able to explain most of the currently observable properties of the circumstellar disks of Be stars. However, more stringent tests, focusing on reproducing multitechnique observations of individual…
The spectra of stars with the B[e] phenomenon are dominated by features that are related to physical conditions of circumstellar material around these objects and are not intrinsic to the stars. Previous studies have shown that emission…
Be stars are rapidly rotating B-type stars that exhibit Balmer emission lines in their optical spectra. These stars play an important role in studies of stellar evolution and disk structures. In this work, we carried out a systematic search…
The Be star $\pi$ Aquarii shows peculiar $\gamma$ Cas-type X-ray emission, likely caused by its outer disk interacting with a low-mass companion, probably a white dwarf. We study the long-term variability of its optical spectra to derive…
Circumstellar disks are an essential ingredient of the formation of low-mass stars. It is unclear, however, whether the accretion-disk paradigm can also account for the formation of stars more massive than about 10 solar masses, in which…
Crucial to a quantitative understanding of galaxy evolution are the properties of the inter-stellar medium that regulate galactic-scale star formation activity. We present here the results of a suite of star formation models applied to the…
The geometrical relationship between the distribution of circumstellar matter, observed optical linear polarization, outflows and binary orbital plane in Herbig Ae/Be stars is investigated. Optical linear polarization measurements carried…
Classical Be stars, the "e" standing for the presence of spectroscopic line emission, are main sequence stars of spectral type B that are able to form a gaseous disk in Keplerian motion from star-ejected matter. The main driver of this…
In order to detect and characterise cold extended circumstellar dust originating from collisions of planetesimal bodies in disks, belts, or rings at Kuiper-Belt distances (30-50 AU or beyond) sensitive submillimetre observations are…
We present comprehensive models of Herbig Ae star, HD 142666, which aim to simultaneously explain its spectral energy distribution (SED) and near-infrared (NIR) interferometry. Our new sub-milliarcsecond resolution CHARA (CLASSIC and CLIMB)…
Using the method termed complex asteroseismology, we derive constraints on model atmospheres, in particular, on the NLTE effects. We fit simultaneously pulsational frequencies and the corresponding values of the nonadiabatic complex…