Journal ArticleDOI
Circumstellar molecular envelopes of AGB and post-AGB objects
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TLDR
The physical and chemical structure of CSEs around stars on, and beyond, the asymptotic giant branch (AGB) is discussed in this paper, where the mass loss rate estimate from CO radio line emission is briefly discussed.Abstract:
This review presents the physical and chemical structure of circumstellar envelopes (CSEs) around stars on, and beyond, the asymptotic giant branch (AGB). It focusses on information that is relevant to the interpretation of the molecular line emission from these envelopes. The mass loss rate estimate from CO radio line emission is briefly discussed. It continues with an overview of the morphology and kinematics of AGB and post-AGB CSEs, based on the observational evidence obtained from molecular line emission. Also the small-scale structure of the circumstellar medium is discussed. Finally, a possible scenario for the puzzling, drastic change (at least apparently) from largely spherical AGB-CSEs to the prominent equatorial density enhancements that dominate in CSEs around late post-AGB objects, e.g., planetary nebulae (PNe), is put forward.read more
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Mass Loss from Cool Stars: Impact on the Evolution of Stars and Stellar Populations
TL;DR: In this article, a review emphasizes the mass loss processes that affect the fates of single stars with initial masses between one and nine solar masses and finds that empirical relationships between mass loss rates and stellar parameters are determined mostly by selection effects and tell us which stars are losing mass rather than how stars lose mass.
Journal ArticleDOI
A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants
Nick L. J. Cox,Franz Kerschbaum,A. J. van Marle,L. Decin,L. Decin,D. Ladjal,A. Mayer,Martin Groenewegen,S. Van Eck,Pierre Royer,Roland Ottensamer,Toshiya Ueta,Alain Jorissen,M. Mecina,Zakaria Meliani,Zakaria Meliani,A. Luntzer,Joris Blommaert,Th. Posch,B. Vandenbussche,Christoffel Waelkens +20 more
TL;DR: In this article, different morphologies associated to the interaction of the stellar winds of AGB stars and red supergiants with the interstellar medium (ISM) are identified, and basic parameters affecting the morphology are discussed.
Journal ArticleDOI
Models of circumstellar molecular radio line emission - Mass loss rates for a sample of bright carbon stars
Fredrik L. Schöier,Hans Olofsson +1 more
TL;DR: In this paper, a detailed radiative transfer analysis, combined with an energy balance equation for the gas, was performed to determine some of the basic parameters that characterize circumstellar envelopes, e.g., the stellar mass loss rate, the gas expansion velocity, and the kinetic temperature structure of the gas.
Journal ArticleDOI
Models of circumstellar molecular radio line emission: Mass loss rates for a sample of bright carbon stars
F. L. Schoeier,Hans Olofsson +1 more
TL;DR: In this paper, a detailed radiative transfer analysis, combined with an energy balance equation for the gas, was performed to determine some basic parameters that characterize circumstellar envelopes (CSEs), e.g., the stellar mass loss rate, the gas expansion velocity, and the kinetic temperature structure of the gas.
Journal ArticleDOI
Production of dust by massive stars at high redshift
TL;DR: In this article, the authors identify and quantify the most important stellar channels of rapid dust formation and provide analytical expressions for the dust production efficiency of stars in the mass range 3-40m.
References
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Journal ArticleDOI
A survey of interstellar H I from L-alpha absorption measurements. II
TL;DR: The Copernicus satellite surveyed the spectral region near L alpha to obtain column densities of interstellar HI toward 100 stars as discussed by the authors, and the value of the mean ratio of total neutral hydrogen to color excess was found to equal 5.8 x 10 to the 21st power atoms per (sq cm x mag).
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The photodissociation and chemistry of interstellar CO
E. F. van Dishoeck,John H. Black +1 more
TL;DR: In this paper, the effects of line broadening, self-shielding, shielding by H and H2, and isotope-selective shielding are examined as functions of depth into interstellar clouds.
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Dynamical modeling of long-period variable star atmospheres
TL;DR: In this paper, numerical calculations were performed to investigate the dynamical structure and behavior of a spherical model atmosphere for cool pulsating Mira-like stars with masses from 0.8 to 2.0 solar masses and fundamental-mode pulsation periods from 175 to 1000 days.
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Mass Loss from Evolved Stars. III. Mass Loss Rates for 50 Stars from CO J = 1--0 Observations: Erratum
G. R. Knapp,Mark Morris +1 more
TL;DR: In this article, a 2.6 mm de longueur d'onde dans les directions de 105 etoiles evoluees froides was detected, in the presence of Mira of type M, deux sont des supergeantes, and le rest of them S ou carbone.
Journal ArticleDOI
The Photodissociation of CO in Circumstellar Envelopes
TL;DR: In this article, the CO photodissociation rate for the unshielded ISM was calculated using recent laboratory results which confirm that photodeissociation occurs by way of line absorption, and a value of 2.0 x 10 to the -10th/s was obtained.