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Related papers: Dynamic model atmospheres of cool giants

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The evolution and spectral properties of stars on the AGB are significantly affected by mass loss through dusty stellar winds. Dynamic atmosphere and wind models are an essential tool for studying these evolved stars, both individually and…

Solar and Stellar Astrophysics · Physics 2014-07-02 Kjell Eriksson , Walter Nowotny , Susanne Höfner , Bernhard Aringer , Astrid Wachter

The recent progress in high-spatial-resolution techniques, spanning wavelengths from the visual to the radio regime, is leading to new valuable insights into the complex dynamical atmospheres of Asymptotic Giant Branch (AGB) stars and their…

Solar and Stellar Astrophysics · Physics 2016-10-28 Susanne Höfner

The slow, dense winds observed in evolved asymptotic giant branch (AGB) stars are usually attributed to a combination of dust formation in the dynamical inner atmosphere and momentum transfer from stellar photons interacting with the newly…

Solar and Stellar Astrophysics · Physics 2019-06-26 Sara Bladh

Since about 25 years ago work has been dedicated to the development of hydrodynamical model atmospheres for cool stars (of A to T spectral type). Despite their obviously sounder physical foundation in comparison with standard hydrostatic…

Astrophysics · Physics 2007-05-23 H. -G. Ludwig , A. Kucinskas

The winds observed around asymptotic giant branch (AGB) stars are generally attributed to radiation pressure on dust, which is formed in the extended dynamical atmospheres of these pulsating, strongly convective stars. Current…

Solar and Stellar Astrophysics · Physics 2022-12-07 Susanne Höfner , Bernd Freytag

Late type giants (RGB/AGB stars) will be important tracers of the Galactic morphology and evolution in the framework of Gaia, as they are intrinsically bright and thus can probe distant stellar populations or those obscured by interstellar…

Atmospheres of evolved AGB stars are heavily affected by pulsation, dust formation and mass loss, and they can become very extended. Time series of observed high-resolution spectra proved to be a useful tool to study atmospheric dynamics…

Astrophysics · Physics 2009-11-10 W. Nowotny , B. Aringer , S. Hoefner , R. Gautschy-Loidl , W. Windsteig

Cool luminous giants, in particular asymptotic giant branch stars, are among the most important sources of cosmic dust. Their extended dynamical atmospheres are places where grains form and initiate outflows driven by radiation pressure,…

Solar and Stellar Astrophysics · Physics 2009-03-31 S. Hoefner

The intricate interplay of atmospheric shock waves and a complex, variable radiation field with non-equilibrium dust formation presents a considerable challenge to self-consistent modelling of atmospheres and winds of AGB stars.…

Astrophysics · Physics 2007-05-23 S. Hoefner

We discuss and illustrate contributions that optical interferometry has made on our current understanding of cool evolved stars. We include red giant branch (RGB) stars, asymptotic giant branch (AGB) stars, and red supergiants (RSGs).…

Solar and Stellar Astrophysics · Physics 2015-10-28 Markus Wittkowski , Claudia Paladini

We present self-consistent dynamical models for dust driven winds of carbon-rich AGB stars. The models are based on the coupled system of frequency-dependent radiation hydrodynamics and time-dependent dust formation. We investigate in…

Astrophysics · Physics 2007-05-23 A. C. Andersen , S. Hoefner , R. Gautschy-Loidl

The wind-driving mechanism of asymptotic giant branch (AGB) stars is commonly attributed to a two-step process: first, gas in the stellar atmosphere is levitated by shockwaves caused by stellar pulsation, then accelerated outwards by…

Solar and Stellar Astrophysics · Physics 2018-11-07 S. Liljegren , S. Höfner , B. Freytag , S. Bladh

Originating in different depths of the very extended atmospheres of AGB stars, various molecular spectral lines observable in the near-infrared show diverse behaviours and can be used to probe atmospheric dynamics throughout the outer…

Astrophysics · Physics 2009-11-10 W. Nowotny , T. Lebzelter , J. Hron , S. Hoefner

We investigate the observable characteristics of the extended atmospheres of AGB stars across a wide range of radio and (sub-)mm wavelengths using state-of-the-art 1D dynamical atmosphere and wind models over one pulsation period. We also…

Solar and Stellar Astrophysics · Physics 2024-11-21 Behzad Bojnordi Arbab , Wouter Vlemmings , Theo Khouri , Susanne Höfner

While the basic properties of AGB stellar evolution are well established, comprehensive observational studies of late phases of intermediate mass stars continue to generate puzzles for current stellar models. Here, I review current…

Astrophysics · Physics 2007-05-23 Falk Herwig

Convection and mass loss by stellar winds are two dynamical processes that shape asymptotic giant branch (AGB) stars and their evolution. Observations and earlier 3D models indicate that giant convection cells cause high-contrast surface…

Solar and Stellar Astrophysics · Physics 2023-01-30 Bernd Freytag , Susanne Höfner

We present self-consistent dynamical models for dust-driven winds of carbon-rich AGB stars. The models are based on the coupled system of frequency-dependent radiation hydrodynamics and time-dependent dust formation. We investigate in…

Astrophysics · Physics 2009-04-17 A. C. Andersen , S. Hoefner , R. Gautschy-Loidl

(abbreviated) Measuring the surface abundances of AGB stars is an important tool for studying the effects of nucleosynthesis and mixing in the interior of low- to intermediate mass stars during their final evolutionary phases. The…

Solar and Stellar Astrophysics · Physics 2015-05-18 T. Lebzelter , W. Nowotny , S. Höfner , M. T. Lederer , K. H. Hinkle , B. Aringer

[Abridged] AGB stars are significant contributors to the metal enrichment of the interstellar medium. In this paper, we adapted models from advanced RHD simulations as input for radiative transfer software to create synthetic observables. A…

Solar and Stellar Astrophysics · Physics 2024-10-09 Joachim Wiegert , Bernd Freytag , Susanne Höfner

For amorphous carbon several laboratory extinction data are available, which show quite a wide range of differences due to the structural complexity of this material. We have calculated self-consistent dynamic models of circumstellar…

Astrophysics · Physics 2007-05-23 Anja C. Andersen , Rita Loidl , Susanne Hofner
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