Pulsation and Mass Loss

Dorfi, E. A.; Höfner, Susanne; Feuchtinger, M. U.

doi:10.1007/978-94-015-9698-5_5

Cited by 37 publications

(56 citation statements)

References 11 publications

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“…It would be prudent to compare predictions for the velocity spatial profile and relationships among dynamical and spectral quantities produced by more elaborate models (e.g. Fleischer, Winters & Sedlmayr 1999;Höfner 1999;Dorfi et al 2001). Such a comparison would help identify which features in these complex models are simply direct consequences of energy and momentum conservation, and which are unique to detailed modelling of various physical and chemical effects.…”

Section: Discussionmentioning

confidence: 99%

“…Proper description of these processes should be followed by grain formation and growth, and subsequent wind dynamics. Two ambitious programs attempting to incorporate as many aspects of this formidable task as possible have been conducted over the last decade by groups at Berlin (see Winters et al 2000;Wachter et al 2008; and references therein) and Vienna (see Höfner 1999;Dorfi et al 2001;Höfner et al 2003;Nowotny et al 2005; and references therein). While much has been accomplished, the complexity of this undertaking necessitates simplifications such as a pulsating boundary.…”

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confidence: 99%

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Dusty winds - II. Observational implications

Ivezić

Elitzur

2010

Monthly Notices of the Royal Astronomical Society

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We compare observations of asymptotic giant branch stars and predictions of the Elitzur & Ivezić steady‐state radiatively driven dusty wind model. The model results are described by a set of similarity functions of a single independent variable, and imply general scaling relations among the system parameters. We find that the model properly reproduces various correlations among the observed quantities and demonstrates that dust drift through the gas has a major impact on the structure of most winds. From data for nearby oxygen‐rich and carbon‐rich mass‐losing stars we find that (1) the dispersion in grain properties within each group is rather small; (2) both the dust cross‐section per gas particle and the dust‐to‐gas mass ratio are similar for the two samples even though the stellar atmospheres and grain properties are very different; (3) the dust abundance in both outflows is significantly below the Galactic average, indicating that most of the Galactic dust is not stardust – contrary to popular belief, but in support of Draine. Our model results can be easily applied to recent massive data sets, such as the Spitzer SAGE survey of the Large Magellanic Cloud, and incorporated in galaxy evolution models.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Dusty winds - II. Observational implications

Ivezić

Elitzur

2010

Monthly Notices of the Royal Astronomical Society

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“…Again assuming f = 1/3, we obtain radiative hydrodynamics with a non-equilibrium diffusion approximation. The approximation was used in the models by Dorfi & Feuchtinger (1991). In this paper, instead, we numerically solve the radiative transfer equations for a spherical geometry to evaluate the factor.…”

Section: Moment Equations Of Radiative Transfermentioning

confidence: 99%

Linear and nonlinear pulsation models with the variable Eddington factor approximation of radiative hydrodynamics

Aikawa¹

2008

A&A

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Context. Linear and also nonlinear pulsation models with the variable Eddington factor approximation of the radiative transfer are constructed. Aims. The aim of the study is to apply hydrodynamic models of radial pulsation to the observed variability in some post-AGB stars. It has been shown that the pulsation behavior could be strongly effected by the radiative field of the envelope of these stars because of high luminosity in these low mass supergiant stars. Thus, it is important to treat the radiative field with a higher approximation than the diffusion approximation which has been used successfully in classical Cepheids. Methods. The moment equations of radiative transfer are integrated into the hydrodynamic equations with a variable Eddington factor. The factor is calculated independently by solving the transfer equation of spherical geometry. The linear eigen value problem of the radial perturbation from hydrostatic equilibrium is solved, and nonlinear simulations of radial pulsation are performed with the same approximation of the radiative transfer. The method is applied to pulsation of low mass supergiant stars and, for comparison, classical Cepheids.Results. The properties of the strange modes that appear often in low mass supergiant star models e.g. post-AGB stars are seriously affected by different treatments of the radiative field in the linear analyses and nonlinear simulations.

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“…Dorfi et al 2001) we emphasize that in general the observations of variable stars with large amplitude pulsations cannot be interpreted by simple hydrostatic atmospheric models. The stratification of the outer stellar layers is strongly modified by the shock waves, which heat and accelerate the atmospheric material.…”

Section: Discussionmentioning

confidence: 91%

Pulsations of Luminous Blue Variables

Dorfi

Gautschy

2007

Veröffentlichungen Der Kommission Für Astronomie

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From simulations of massive stars we find regular low-amplitude radial pulsations can be excited. Such pulsations were encountered during core hydrogen burning as well as during the early core helium burning stage of evolution. For four selected models we present light curves in the V-band. The results are discussed with the aim to guide observations to identify and monitor such regularly pulsating variable massive stars in nature.

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Pulsation and Mass Loss

Cited by 37 publications

References 11 publications

Dusty winds - II. Observational implications

Dusty winds - II. Observational implications

Linear and nonlinear pulsation models with the variable Eddington factor approximation of radiative hydrodynamics

Pulsations of Luminous Blue Variables

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