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Interferometric observations of large biologically interesting interstellar and cometary molecules. [PDF]
Proc Natl Acad Sci U S A, 2006 Snyder LE.
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Spatial and velocity structure of circumstellar water masers
New Astronomy Reviews, 1999We discuss the results of our study of water masers at 22 GHz with the Very Large Array. We conclude, from the anticorrelation between the intensity and linewidth of the maser features, that they are unsaturated; turbulence must exist in order to explain the large observed opacities.
F. Colomer +3 more
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Polarization observations of circumstellar OH masers
Astronomy Reports, 2010Results of observations of circumstellar OH masers in lines with wavelengths near 18 cm are reported. The observations were carried out on the radio telescope of the Nan cay Radio Astronomy Observatory (France). In 2007–2009, 70 late-type stars were observed (including Mira and semi-regular variables). For 53 of these, emission was detected in at least
Rudnitskii, G. M. +2 more
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1993
The use of OH masers as probes of circumstellar envelopes is briefly discussed, with special emphasis on the mainlines at 1665 and 1667 MHz. In general these are inverted nearer to the star than the 1612 MHz masers, and the envelope structure they reveal is more irregular and asymmetric.
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The use of OH masers as probes of circumstellar envelopes is briefly discussed, with special emphasis on the mainlines at 1665 and 1667 MHz. In general these are inverted nearer to the star than the 1612 MHz masers, and the envelope structure they reveal is more irregular and asymmetric.
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1993
The circumstellar envelopes of a sample red giants and supergiants have been investigated using MERLIN 22GHz H2O maser observations and single dish observations of the 22, 321, and 325GFfz water maser lines. The MERLIN data shows that inner circumstellar envelopes are generally asymmetrical with evidence for discs and bipolar outflows among the ...
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The circumstellar envelopes of a sample red giants and supergiants have been investigated using MERLIN 22GHz H2O maser observations and single dish observations of the 22, 321, and 325GFfz water maser lines. The MERLIN data shows that inner circumstellar envelopes are generally asymmetrical with evidence for discs and bipolar outflows among the ...
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Models of Circumstellar Masers
1998Abstract Maser emission involving SiO, H2O and OH has been observed in the direction of a large number of AGB stars. These stars have the characteristic that they lose mass with rates between 10-8 solar masses per year to as much as 10.,..4 solar masses per year. Maser emission may occur in the circumstellar envelope (CSE) of AGB.
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Optical pumping of circumstellar SiO masers
1995We investigate the influence of the photospheric line spectrum on the optical pumping of circumstellar CO. As pump radiation we consider in particular the photospheric spectrum of a cool carbon star (T eff =2600 K). This spectrum shows deep absorption lines in the wavelength range of the pump lines (4.6 μ). Of particular importance for the pump process
E. Rausch, W. H. Kegel, T. Tsuji
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Amplification of stellar background by circumstellar masers
Astrophysics and Space Science, 1988The calculations with the use of simple maser model show that the stellar background contributes negligibly to the mean peak intensities at 1612 MHz. Under some conditions, however, the contribution from the central star may constitute a few percent of the mean peak intensity.
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Circumstellar Masers in the Galactic Center
2003Blind and targeted surveys for maser emission (OH, H2O, and SiO) in the central degree (≤ 150 pc) of the Galactic center will be discussed, with the emphasis on masers in OH/IR stars. Using the masers, some recent clues about the kinematics and evolution of the central part of the Milky Way galaxy will be given.
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Molecular catastrophes and circumstellar SiO masers
1993Understanding the complex SiO maser regions of highly evolved stars can be improved through multiwavelength studies of 'premaser' stars, such as M0-M4 giants and semiregular variables, which can be placed on normal H-R diagrams unlike most of the OH-IR stars.
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