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The asymptotic giant branch (AGB) star R Sculptoris (R Scl) is one of the most extensively studied stars on the AGB. R Scl is a carbon star with a massive circumstellar shell ($M_{shell}\sim 7.3\times10^{-3}~M_{\odot}$) which is thought to…

Astrophysics of Galaxies · Physics 2018-01-10 Matthew J. Hankins , Terry L. Herter , Matthias Maercker , Ryan M. Lau , Gregory C. Sloan

The mass-loss mechanisms in M-type AGB stars are not well understood, in particular, the formation of dust-driven winds from the innermost gaseous layers around these stars. One way to understand the gas-dust interaction in these regions…

We study the circumstellar environment of the M-type AGB star RT Vir using mid-infrared high spatial resolution observations from the ESO-VLTI focal instrument MIDI. The aim of this study is to provide observational constraints on…

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

By using self-consistent dynamic model atmospheres which simulate pulsation-enhanced dust-driven winds of AGB stars we studied in detail the influence of (i) pulsations of the stellar interiors, and (ii) the development of dusty stellar…

Solar and Stellar Astrophysics · Physics 2015-05-27 Walter Nowotny , Bernhard Aringer , Susanne Höfner , Michael T. Lederer

Modeling stellar atmospheres is a complex, intriguing task in modern astronomy. A systematic comparison of models with multi-technique observations is the only efficient way to constrain them. Aims: We performed a self-consistent modeling…

Solar and Stellar Astrophysics · Physics 2017-04-12 Gioia Rau , Josef Hron , Claudia Paladini , Benard Aringer , Kjell Eriksson , Paola Marigo , Walter Nowotny , Rebekka Grellmann

We present near-infrared interferometry of the carbon-rich asymptotic giant branch (AGB) star R Sculptoris. The visibility data indicate a broadly circular resolved stellar disk with a complex substructure. The observed AMBER squared…

With the help of model calculations we aim at reproducing the observational photometric findings for a large sample of well-characterised galactic C-type Mira variables losing mass at different rates. We used dynamic model atmospheres,…

Solar and Stellar Astrophysics · Physics 2015-06-15 W. Nowotny , B. Aringer , S. Hoefner , K. Eriksson

Context. We study the atmosphere of the carbon-rich Mira RU Vir using the mid-infrared high spatial resolution interferometric observations from VLTI/MIDI. Aims. The aim of this work is to analyse the atmosphere of the carbon-rich Mira RU…

Solar and Stellar Astrophysics · Physics 2015-11-04 G. Rau , C. Paladini , J. Hron , B. Aringer , M. A. T. Groenewegen , W. Nowotny

Molecules and dust produced by the atmospheres of cool evolved stars contribute to a significant amount of the total material found in the interstellar medium. To understand the mechanism behind the mass loss of these stars, it is of…

Solar and Stellar Astrophysics · Physics 2019-09-11 Gioia Rau , Keiichi Ohnaka , Markus Wittkowski , Vladimir Airapetian , Kenneth G. Carpenter

Context. SV Psc is an asymptotic giant branch (AGB) star surrounded by an oxygen-rich dust envelope. The mm-CO line profile of the object's outflow shows a clear double-component structure. Because of the high angular resolution, mid-IR…

Solar and Stellar Astrophysics · Physics 2015-06-04 D. Klotz , S. Sacuto , F. Kerschbaum , C. Paladini , H. Olofsson , J. Hron

The mechanism of mass loss in late evolutionary stages of low- and intermediate-mass stars is not yet well understood. Therefore, it is crucial to study the dynamics of the region within a few stellar radii, where the wind acceleration is…

Solar and Stellar Astrophysics · Physics 2019-10-02 Keiichi Ohnaka , Gerd Weigelt , Karl-Heinz Hofmann

For the carbon AGB star R Sculptoris, the uncertain distance significantly affects the interpretation of observations regarding the evolution of the stellar mass loss during and after the most recent thermal pulse. We aim to provide a new,…

Solar and Stellar Astrophysics · Physics 2018-04-18 M. Maercker , M. Brunner , M. Mecina , E. De Beck

For the Mass-loss of Evolved StarS (MESS) programme, the unprecedented spatial resolution of the PACS photometer on board the Herschel space observatory was employed to map the dusty environments of asymptotic giant branch (AGB) and red…

We obtained a total of 20 near-infrared K-band spectro-interferometric snapshot observations of the Mira variables o Cet, R Leo, R Aqr, X Hya, W Vel, and R Cnc with a spectral resolution of about 1500. We compared observed flux and…

Solar and Stellar Astrophysics · Physics 2016-02-17 M. Wittkowski , A. Chiavassa , B. Freytag , M. Scholz , S. Hoefner , I. Karovicova , P. A. Whitelock

This paper presents interferometric and single-dish CO observations along with HI data obtained for the oxygen-rich semi-regular variable RS Cnc, in order to probe its circumstellar environment at different scales. With the Plateau de Bure…

Solar and Stellar Astrophysics · Physics 2015-05-18 Yannick Libert , Jan Martin Winters , Thibaut Le Bertre , Eric Gérard , Lynn D. Matthews

We study the close circumstellar environment of the nearby S-type star Pi^1 Gruis using high spatial-resolution, mid-infrared observations from the ESO/VLTI. Spectra and visibilities were obtained with the MIDI interferometer on the VLT…

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
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