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Related papers: Non-isothermal effects on Be disks

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We investigate the continuum emission of viscous decretion discs around Be stars in this paper. The results obtained from non-LTE (local thermodynamic equilibrium) radiative transfer models show two regimes in the disc surface brightness…

Solar and Stellar Astrophysics · Physics 2015-10-16 Rodrigo G. Vieira , Alex C. Carciofi , Jon E. Bjorkman

We present an analysis of the near-infrared continuum emission from the circumstellar gas disks of Be stars using a radiative transfer code for a parametrized version of the viscous decretion disk model. This isothermal gas model creates…

Solar and Stellar Astrophysics · Physics 2015-05-27 Y. Touhami , D. R. Gies , G. H. Schaefer

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…

We discuss the basic hydrodynamics that determines the density structure of the disks around hot stars. Observational evidence supports the idea that these disks are Keplerian (rotationally supported) gaseous disks. A popular scenario in…

Astrophysics · Physics 2009-11-13 A. C. Carciofi , J. E. Bjorkman

We investigated the properties of $80$ Be star disks, using the time dependent viscous decretion disk (VDD) model to interpret their mid-infrared continuum fluxes. Besides estimating the typical parameter ranges for such disks, this…

Solar and Stellar Astrophysics · Physics 2017-07-12 Rodrigo G. Vieira , Alex C. Carciofi

There is an increasing body of evidence that suggests that Be disks are well described by the Viscous Decretion Disk (VDD) model according to which the formation and structure of the disk depend on the kinematic viscosity of the gas.…

Solar and Stellar Astrophysics · Physics 2018-11-07 Mohammad Reza Ghoreyshi

The observed emission lines of Be stars originate from a circumstellar Keplerian disk that are generally well explained by the Viscous Decretion Disk model. In an earlier work we performed the modeling of the full light curve of the bright…

Solar and Stellar Astrophysics · Physics 2021-03-24 Mohammad R. Ghoreyshi , Alex C. Carciofi , Carol E. Jones , Daniel M. Faes , Dietrich Baade , Thomas Rivinius

We apply the viscous decretion disc (VDD) model to interpret the infrared disc continuum emission of 80 Be stars observed in different epochs. In this way, we determined 169 specific disc structures, namely their density scale, $\rho_0$,…

Solar and Stellar Astrophysics · Physics 2017-07-11 Rodrigo G. Vieira , Alex C. Carciofi , Jon E. Bjorkman , Thomas Rivinius , Dietrich Baade , Leandro R. Rímulo

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…

We revisit the viscous decretion disk (VDD) model of the classical Be star $\beta$ CMi as presented by \citet{klement} using an updated version of the radiative transfer code {\ttfamily HDUST}. A software bug was causing the mean…

Solar and Stellar Astrophysics · Physics 2017-03-22 Robert Klement , Alex Cavalieri Carciofi , Thomas Rivinius

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…

Be stars possess gaseous circumstellar disks that modify in many ways the spectrum of the central B star. Furthermore, they exhibit variability at several timescales and for a large number of observables. Putting the pieces together of this…

Solar and Stellar Astrophysics · Physics 2015-06-05 X. Haubois , A. C. Carciofi , Th. Rivinius , A. T. Okazaki , J. E. Bjorkman

Circumstellar discs of Be stars are thought to be formed from material ejected from a fast-spinning central star. This material possesses large amounts of angular momentum and settles in a quasi-Keplerian orbit around the star. This simple…

Solar and Stellar Astrophysics · Physics 2015-05-20 Alex C. Carciofi

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…

Astrophysics · Physics 2007-05-23 John M. Porter

The non-LTE state of the hydrogen gas in isothermal transonic decretion disks around a B1V star has been calculated by an iterative method in order to explore the basic physical process in the disk. This dynamical model is characterized by…

Astrophysics · Physics 2015-05-13 Hidetoshi Iwamatsu , Ryuko Hirata

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 present infra-red (JHK) photometry of 52 isolated Be stars of spectral types O9--B9 and luminosity classes III--V. We describe a new method of reduction, enabling separation of interstellar reddening and circumstellar excess. Using this…

Astrophysics · Physics 2009-11-06 Lee Howells , I. A. Steele , John M. Porter , J. Etherton

Two models of the circumstellar disc around supergiant B[e] stars are discussed: an equatorial wind model produced by wind bi-stability, and a Keplerian viscous disc model. Both models are successful in providing a site for dust formation…

Astrophysics · Physics 2009-11-07 John M. Porter

In this work we explore the effect of binarity in the decretion disc of Be stars, in order to explain their variability. To this aim, we performed smoothed particle hydrodynamics (SPH) simulations on Be binary systems, following the matter…

Solar and Stellar Astrophysics · Physics 2016-10-31 Despina Panoglou , Daniel M. Faes , Alex C. Carciofi , Atsuo T. Okazaki , Thomas Rivinius

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…

Solar and Stellar Astrophysics · Physics 2017-02-24 Mohammad Reza Ghoreyshi , Alex Cavalieri Carciofi
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