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The Chemical Composition of Carbon Stars. The R-Type Stars [PDF]
Astronomy and Astrophysics, 2009 The aim of this work is to shed some light on the problem of the formation of carbon stars of R-type from a detailed study of their chemical composition. We use high-resolution and high signal-to-noise optical spectra of 23 R-type stars selected from the Hipparcos catalogue. The chemical analysis is made using spectral synthesis in LTE and state-of-the-
Sergio Cristallo +2 more
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On the Carbon-Star Status of Five Stars in a New Carbon Star Catalog
Chinese Journal of Astronomy and Astrophysics, 2002We find that five sources listed in the new carbon star catalog are not really carbon-rich objects but oxygen-rich stars, because they all have the prominent 10mum silicate features in absorption and the 1612 MHz OH maser emission or/and the SiO molecular features.
Pei-Sheng Chen, Yi-Fei Gao
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Annual Review of Astronomy and Astrophysics, 1998
▪ Abstract Absolute magnitudes are estimated for carbon stars of various subtypes in the Hipparcos catalogue and as found in the Magellanic Clouds. Stellar radii fall within the limits of 2.4–4.7 AU. The chemical composition of carbon stars indicates that the C-N stars show nearly solar C/H, N/H, and 12C/13C ratios.
George Wallerstein, Gillian R. Knapp
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▪ Abstract Absolute magnitudes are estimated for carbon stars of various subtypes in the Hipparcos catalogue and as found in the Magellanic Clouds. Stellar radii fall within the limits of 2.4–4.7 AU. The chemical composition of carbon stars indicates that the C-N stars show nearly solar C/H, N/H, and 12C/13C ratios.
George Wallerstein, Gillian R. Knapp
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Infrared Velocities of Carbon Stars
Astrophysics and Space Science, 1994We have measured radial velocities of infrared photospheric lines observed in 37 bright carbon stars. The spectra were obtained on the Kitt Peak National Observatory 4 meter telescope with Fourier transform spectrometers between 1976 and 1988. The observations have a typical resolution of 65000 and a typical signal-to-noise ratio of 50. All the spectra
C. Barnbaum, K. Hinkle
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Carbon stars in infrared surveys
Astrophysics and Space Science, 1994In order to prepare the analysis of the forthcoming near-IR surveys (DENIS, 2MASS) and to interpret them in terms of galactic structure and AGB evolution, we present model predictions of AGB distributions in K, in 12µm and in (J-K, [12–25]) space, as they will be obtained from these surveys, cross-correlated with IRAS Catalog. The simulations have been
F. Guglielmo, A. C. Robin
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Amorphous carbon around carbon stars
Astrophysics and Space Science, 1987In this paper we present the results of a simplified model to determine the flux emerging from dust envelopes around cool stars. The model proposed holds under the hypotheses of negligible scattering effects and spherical geometry of the dust cloud.
OROFINO, Vincenzo +3 more
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Carbon Dioxide in Star-forming Regions
The Astrophysical Journal, 2000We consider the gas-phase chemistry of CO2 molecules in active regions. We show that CO2 molecules evaporated from dust in hot cores cannot be efficiently destroyed and are in fact copiously produced in cooler gas. When CO2-rich ices are sputtered in strong MHD shock waves, the increase in atomic hydrogen, due to H2 dissociation by ion-neutral ...
, Charnley, , Kaufman
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Oxygen and carbon abundances for the WO stars
Space Science Reviews, 1994We present relative carbon and oxygen abundances derived via an optically thin recombination line analysis for five WO stars, and compare the derived abundances to recent evolutionary models. New recombination coefficients for O4+, O5+ and O6+ ions have allowed total oxygen abundances to be derived.
Robin L. Kingsburgh +2 more
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