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The Circumstellar Envelope of VX Sagittarii
1986Radio maser emission from OH, H2O and SiO masers provides a means of studying the circumstellar envelopes of long period variable stars. The OH 1612 MHz maser emission arises in the cool outer layers of the envelopes at distances >101 6cm from the photosphere and is pumped by infrared photons (Elitzur 1982). The maser lines of the OH molecule at 1665/7
Jessica M. Chapman, R. J. Cohen
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The Physical and Chemical Properties of Circumstellar Envelopes
Astrophysics and Space Science, 1995An overview is given of recent results on some basic properties of the circumstellar envelopes of evolved stars. The focus is on well studied examples which illustrate envelopes of different types and at different stages of evolution. The close connection between the physical and chemical properties of the envelopes is emphasized.
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The circumstellar envelope of VX Sgr
Astrophysics and Space Science, 1992By use of the data for VLBI observation of SiO masrs, and MERLIN observation of H2O and OH masers of VX Sgr, we found that the SiO, H2O, OH 1665/7, OH 1612 masers occur on a few separated shells, and the order of magnitude of the radii of their corresponding shells is 1014, 1015, 1016 cm, respectively.
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A survey of CN in circumstellar envelopes
Astronomy & Astrophysics, 1997We have conducted a survey of CN N=2-1 and N=1-0 line emission in the envelopes of evolved stars. The sample consists of 42 objects, including C-rich and O-rich envelopes, S-stars, detached envelopes, and proto-planetary nebulae. Confident detections have been achieved in 30 objects.
Bachiller, R +6 more
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Chemistry in Expanding Circumstellar Envelopes
1988This review is concerned with the chemistry occurring in the. expanding envelopes around cool, late-type stars. We show that, although many different chemical processes help determine the overall chemical composition of such envelopes, the detailed composition, as evidenced by the many molecules detected at radio wavelengths, is best explained by a ...
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Models for the Circumstellar Envelopes of Be Stars
1976A survey is presented of the theoretical attempts to determine the structure of the circumstellar matter around Be stars. The general equations describing the structure and dynamics of Be star envelopes are given. The complications introduced by various physical phenomena are briefly discussed and initial attempts to solve restricted problems are ...
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Sulphur molecules in the circumstellar envelopes of M-type AGB stars
Astronomy and Astrophysics, 2016Taissa Danilovich +2 more
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