A 12CO ($J=1\rightarrow 0$) and ($J=2\rightarrow 1$) atlas of circumstellar envelopes of AGB and post-AGB stars
نویسندگان
چکیده
منابع مشابه
Imaging the circumstellar envelopes of AGB stars ⋆
Aims. We report the results of an exploratory program to image the extended circumstellar envelopes of asymptotic giant branch (AGB) stars in dust-scattered galactic light. The goal is to characterize the morphology of the envelopes as a probe of the mass-loss process. Methods. The observations consist of short exposures with the VLT and longer exposures with 1–2 m telescopes, augmented with ar...
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Aims. Given their photospheric origin and refractive nature, SiS molecules can provide important constraints on the relative roles of dust condensation and non-equilibrium processes in regulating the chemistry in circumstellar envelopes around evolved stars. Methods. New SiS multi-transition (sub-)millimetre line observations of a sample of AGB stars with varying photospheric C/Oratios and mass...
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We construct a data base of 125 post-AGB objects (including R CrB and extreme helium stars) with published photospheric parameters (effective temperature and gravity) and chemical composition. We estimate the masses of the postAGB stars by comparing their position in the (log Teff , log g) plane with theoretical evolutionary tracks of different masses. We construct various diagrams, with the ai...
متن کاملVLA Observations of H i in the Circumstellar Envelopes of AGB Stars
We have used the Very Large Array (VLA) to search for neutral atomic hydrogen (H i) in the circumstellar envelopes of five asymptotic giant branch (AGB) stars. We have detected H i 21-cm emission coincident in both position and velocity with the S-type semi-regular variable star RS Cnc. The emission comprises a compact, slightly elongated feature centered on the star with a mean diameter of ∼ 8...
متن کاملInfrared Spectroscopic Study of a Selection of AGB and Post-AGB Stars
We present here near-infrared spectroscopy in the H and K bands of a selection of nearly 80 stars that belong to various AGB types, namely S type, M type and SR type. This sample also includes 16 Post-AGB (PAGB) stars. From these spectra, we seek correlations between the equivalent widths of some important spectral signatures and the infrared colors that are indicative of mass loss. Repeated sp...
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ژورنال
عنوان ژورنال: Astronomy and Astrophysics Supplement Series
سال: 1998
ISSN: 0365-0138,1286-4846
DOI: 10.1051/aas:1998213