Showing papers by "Charles H. Townes published in 1977"
TL;DR: In this paper, it was shown that the dynamics of the ionized gas is dominated by the gravitational potential of the massive core at the galactic center and that the total mass within a radius of 1 pc about the galactic centre is estimated to be of the order of 4 million solar masses.
Abstract: Recent observations of the 12.8-micron Ne II emission from the galactic center have revealed a region of primarily blueshifted emission in addition to the previously detected redshifted emission. It appears most likely that the blueshifted and redshifted emission come from separate clouds and that the dynamics of the ionized gas is dominated by the gravitational potential of the massive core at the galactic center. On the basis of the velocities and velocity dispersions, the total mass within a radius of 1 pc about the galactic center is estimated to be of the order of 4 million solar masses.
56 citations
TL;DR: Using the technique of heterodyne interferometry, measurements were made of the spatial distribution of 11 micron radiation from four late type stars as discussed by the authors, and the circumstellar shells surrounding VY Canis Majoris, alpha Orionis, and alpha Scorpii were resolved.
Abstract: Using the technique of heterodyne interferometry, measurements were made of the spatial distribution of 11 micron radiation from four late type stars. The circumstellar shells surrounding VY Canis Majoris, alpha Orionis, and alpha Scorpii were resolved, whereas that of R Leonis was only partially resolved at a fringe spacing of 0.4 sec.
47 citations
TL;DR: In this article, an imaging upconverter for the study of the thermal 10-micron radiation from astronomical sources was constructed, where the infrared radiation is converted to visible radiation by mixing in a 1-cm-long proustite crystal.
Abstract: An imaging upconverter has been constructed which is suitable for use in the study of the thermal 10-micron radiation from astronomical sources. The infrared radiation is converted to visible radiation by mixing in a 1-cm-long proustite crystal. The phase-matched 2-kayser bandpass is tunable from 9 to 11 microns. The conversion efficiency is 2 by 10 to the -7th power and the field of view of 40 arc seconds on the sky contains several hundred picture elements, approximately diffraction-limited resolution in a large telescope. The instrument has been used in studies of the sun, moon, Mercury, and VY Canis Majoris.
42 citations
01 Jan 1977
TL;DR: In this paper, the relative isotopic abundances for C, O, S, N, and Si are found to be similar to those found on Earth, however, there are interesting and provocative differences.
Abstract: The observation of microwave spectra of molecules in interstellar clouds allows separation and detection of the lines of isotopes of many of the more common elements. Comparison of intensities of isotopic lines shows that the relative isotopic abundances for C, O, S, N, and Si are generally rather similar to those found on Earth. However, there are interesting and provocative differences.
5 citations
01 Jan 1977
TL;DR: In this paper, the spatial distribution of 11 micron radiation from omicron Ceti was observed at various phases of its light cycle using a stellar interferometer, which can be attributed to variation in the strength of thermal emission from circumstellar dust relative to the stellar continuum at 11 microns.
Abstract: The spatial distribution of 11 micron radiation from omicron Ceti was observed at various phases of its light cycle using a stellar interferometer. Changes were seen which can be attributed to variation in the strength of thermal emission from circumstellar dust relative to the stellar continuum at 11 microns. These changes are shown to be correlated with the changes in luminosity of omicron Ceti in such a way that dust grain emission at 11 microns was increased more than the continuum during the period of maximum luminosity. The degree of the change in dust grain emission implies that the maximum dust temperature is in the range of 500 K to 700 K during minimum stellar luminosity.
2 citations