Related papers: The Dynamical Evolution of Be star disks
We analyze the intrinsic polarization of two classical Be stars in the process of losing their circumstellar disks via a Be to normal B star transition originally reported by Wisniewski et al. During each of five polarimetric outbursts…
Be stars possess gaseous circumstellar decretion disks, which are well described using standard $\alpha$-disk theory. The Be star 28 CMa recently underwent a long outburst followed by a long period of quiescence, during which the disk…
We present self-consistent solutions for the disk structure of classical Be stars. Our disk model is hydrostatically supported in the vertical direction and the radial structure is governed by viscosity ($\alpha$-disks). We perform…
We analyze the V-band photometry data of the Be star omega CMa, observed during the last four decades. The data is fitted by hydrodynamic models based on the viscous decretion disk (VDD) theory, in which a disk around a fast-spinning Be…
Be stars are main-sequence massive stars with emission features in their spectrum, which originates in circumstellar gaseous discs. Even though the viscous decretion disc (VDD) model can satisfactorily explain most observations, two…
We use a three-dimensional smoothed particle hydrodynamics code to simulate growth and dissipation of Be star discs in systems where the binary orbit is misaligned with respect to the spin axis of the primary star. We investigate six…
We present a new, simple, fast algorithm to numerically evolve disks of inelastically colliding particles surrounding a central star. Our algorithm adds negligible computational cost to the fastest existing collisionless N-body codes, and…
We investigate variations in the linear polarization as well as in the V-band and B-band colour-magnitudes for classical Be star disks. We present two models: disks with enhanced disk density and disks that are tilted or warped from the…
A global disk oscillation implemented in the viscous decretion disk (VDD) model has been used to reproduce most of the observed properties of the well known Be star $\zeta$ Tau. 48 Librae shares several similarities with $\zeta$ Tau -- they…
The Be phenomenon is present in about 20$\%$ of the B-type stars. Be stars show variability on a broad range of timescales, which in most cases is related to the presence of a circumstellar disk of variable size and structure. For this…
Context. The structure of the inner parts of Be star disks (20 stellar radii) is well explained by the viscous decretion disk (VDD) model, which is able to reproduce the observable properties of most of the objects studied so far. The outer…
Be stars are rapidly rotating, with angular frequency around $0.7-0.8$ of their Keplerian break up frequency, as a result of significant accretion during the earlier stellar evolution of a companion star. Material from the equator of the Be…
Classical Be stars are fast rotating, near main sequence B-type stars. The rotation and the presence of circumstellar discs profoundly modify the observables of active Be stars. Our goal is to infer stellar and disc parameters, as well as…
It is assumed that Be star discs are driven by viscosity. Emission from disc models is calculated and is confronted with continuum observations. It is found that the outflowing viscous disc models can reproduce the observed IR continuum…
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…
In the past decade, a consensus has emerged regarding the nature of classical Be stars: They are very rapidly rotating main sequence B stars, which, through a still unknown, but increasingly constrained process, form an outwardly diffusing…
One-armed oscillation modes in the circumstellar discs of Be stars may explain the cyclical variations in their emission lines. We show that a three-dimensional effect, involving vertical motion and neglected in previous treatments,…
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…
Binarity in massive stars has proven to be an important aspect in the their evolution. For Be stars, it might be the cause of their spin up, and thus part of the mechanism behind the formation of their viscous decretion disks. Detecting…
The recent findings of gas giant planets around young A-type stars suggest that disks surrounding Herbig Ae/Be stars will develop planetary systems. An interesting case is HD142527, for which previous observations revealed a complex…