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Related papers: Link between Mass-loss and Variability Type for AG…

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We analyse continuum and molecular emission, observed with ALMA, from the dust-enshrouded intermediate-mass AGB star OH 30.1 -0.7. We find a secondary peak in the continuum maps, "feature B", separated by 4.6" from the AGB star, which…

The outflows of oxygen-rich asymptotic giant branch (AGB) stars are thought to be driven by radiation pressure by photon scattering on grains with sizes of tenths of microns. The details of the formation of dust in the extended atmospheres…

Solar and Stellar Astrophysics · Physics 2018-12-05 T. Khouri , W. H. T. Vlemmings , H. Olofsson , C. Ginski , E. De Beck , M. Maercker , S. Ramstedt

New dynamical models for dust-driven winds of oxygen-rich AGB stars are presented which include frequency-dependent Monte Carlo radiative transfer by means of a sparse opacity distribution technique and a time-dependent treatment of the…

Astrophysics · Physics 2009-11-11 Peter Woitke

We link the onset of pulsation-enhanced, dust-driven winds from asymptotic giant branch (AGB) stars in the Magellanic Clouds to the star's transition between period--luminosity sequences (from B to C'). This transition occurs at ~60 days…

Solar and Stellar Astrophysics · Physics 2019-02-13 Iain McDonald , Michele Trabucchi

This paper describes observations of a new phenomenon in evolved mass-losing AGB stars: the presence of two winds with different expansion velocities. CO(2-1) and CO(3-2) line emission was observed for 45 AGB stars at high velocity…

Astrophysics · Physics 2009-10-30 G. R. Knapp , K. Young , E. Lee , A. Jorissen

Aims: We aim to understand the variation of the surface chemistry that occurs during the AGB phase by analysing results from observations of single post-AGB stars in the Magellanic Clouds. We also aim at reconstruct dust formation…

Solar and Stellar Astrophysics · Physics 2022-11-30 Silvia Tosi , Flavia Dell'Agli , Devika Kamath , Paolo Ventura , Hans Van Winckel , Ester Marini

We present three-component wind models for carbon rich pulsating AGB stars. In particular we study the effects of drift in models of long-period variables, meaning that the dust is allowed to move relative to the gas (drift models). In…

Astrophysics · Physics 2009-11-07 C. Sandin , S. Hoefner

Dust grains forming in the extended atmospheres of AGB stars are critical for the heavy mass loss of these cool luminous giants, as they provide radiative acceleration for the stellar winds. Characteristic mid-IR spectral features indicate…

Solar and Stellar Astrophysics · Physics 2019-03-27 Susanne Höfner , Bernd Freytag

Non-variable OH/IR stars are thought to have just left the asymptotic giant branch (AGB) phase. In this conventional picture, they must still show strong circumstellar extinction caused by the dust ejected during the AGB phase, and the…

ASAS, MACHO, OGLE and SAAO JHKL light curves of 13 stars, that have at some time been classified as D-type symbiotics, are analysed. Most of the near-IR light-curves that have been monitored over many years show long-term changes due to…

Solar and Stellar Astrophysics · Physics 2009-06-24 M. Gromadzki , J. Mikolajewska , P. Whitelock , F. Marang

We have performed high spatial resolution observations of SiO line emission for a sample of 11 AGB stars using the ATCA, VLA and SMA interferometers. Detailed radiative transfer modelling suggests that there are steep chemical gradients of…

Astrophysics · Physics 2007-05-23 F. L. Schoeier , H. Olofsson , T. Wong , D. Fong , M. Lindqvist , L. O. Sjouwerman

Context. The majority of stars that leave the main sequence are undergoing extensive mass loss, in particular during the asymptotic giant branch (AGB) phase of evolution. Observations show that the rate at which this phenomenon develops…

Solar and Stellar Astrophysics · Physics 2015-05-14 Y. Libert , E. Gerard , C. Thum , J. M. Winters , L. D. Matthews , T. Le Bertre

Modelling dust formation in single stars evolving through the carbon-star stage of the asymptotic giant branch (AGB) reproduces well the mid-infrared colours and magnitudes of most of the C-rich sources in the Large Magellanic Cloud (LMC),…

Solar and Stellar Astrophysics · Physics 2021-01-27 F. Dell'Agli , E. Marini , F. D'Antona , P. Ventura , M. A. T. Groenewegen , L. Mattsson , D. Kamath , D. A. García-Hernández , M. Tailo

We study the Galactic distribution of ~10,000 Asymptotic Giant Branch (AGB) stars selected by IRAS colors and variability index. The distance to each star is estimated by assuming a narrow luminosity function and a model-derived bolometric…

Astrophysics · Physics 2009-11-07 T. Jackson , Z. Ivezic , G. R. Knapp

We argue that the energy injection of pulsations may be of greater importance to the mass-loss rate of AGB stars than metallicity, and that the mass-loss trend with metallicity is not as simple as sometimes assumed. Using our detailed…

Astrophysics · Physics 2011-07-21 L. Mattsson , R. Wahlin , S. Höfner , K. Eriksson

It is commonly believed that winds of cool giants in their late evolutionary stages are driven by radiative pressure on dust grains, but the actual grain species responsible for driving winds of M-type AGB stars are still a matter of debate…

Solar and Stellar Astrophysics · Physics 2011-02-28 Sara Bladh , Susanne Höfner , Bernhard Aringer

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

In this paper we present new models of massive stars based on recent advancements in the theory of diffusive mixing and a new empirical formulation of the mass-loss rates of red supergiant stars. We compute two sets of stellar models of…

Astrophysics · Physics 2007-05-23 B. Salasnich , A. Bressan , C. Chiosi

An extensive radiative transfer analysis of circumstellar SiO `thermal' radio line emission from a large sample of M-type AGB stars has been performed. The sample contains 18 irregulars of type Lb (IRV), 7 and 34 semiregulars of type SRa…

This article presents the study of the light-curves extracted from the MACHO database of a sample of stars observed by the ISO in the SMC. These stars belong to the ISO-Mini-Survey catalogue of the Magellanic Clouds (ISO-MCMS, Loup et al.…