Engineering topics

Kinzel, Wayne M.

Publications and source records attributed to Kinzel, Wayne M..

4 records

NASA NTRS1987

Observations of HCN in Comet Halley

Observations of the HCN J = 1-0 rotational transition at 3.4 mm wavelength in comet P/Halley are discussed. The data were obtained during a total of 56 individual observing sessions between Nov. 18, 1985 and May 11, 1986, and represent the first time that a cometary parent molecule has been so extensively monitored. The HCN production rate is well correlated with the total visual magnitude of the comet, indicating that HCN follows the overall gas production. There is also evidence of time variability and variations in the HCN hyperfine ratios from their LTE values. Spectra obtained by binning the HCN data with heliocentric distance show that the HCN line width, and thus the parent outflow velocity, increases with decreasing heliocentric distance.

Schloerb, F. Peter↗

NASA NTRS1987

Search for molecules in Comet Halley at millimeter wavelengths

Data collected with the Five College Radio Astronomy Observatory 13.7-m radio telescope are used to search for the possible CN parent molecules HNC, HC3N, and CH3CN in Comet Halley at millimeter wavelengths. Maximum relative abundances for HNC/HCN of 0.3, for HC3N/HCN of 0.4, and for CH3CN/HCN of 0.8 are obtained, showing that these three molecules are not a major source of the CN radical observed in optical and UV spectroscopy. Upper limits to the beam averaged column densities and production rates of these molecules are determined (in addition to an upper limit for the beam averaged column density for the formyl ion of less than 10 to the 11th/sq cm), providing important constraints for chemical models of the coma.

Swade, Daryl A.↗

NASA NTRS1986

HCN production from Comet Halley

Observations of the HCN J=1-0 rotational transition at 3.4 mm wavelength in comet P/Halley with a 14m antenna were obtained during 56 individual observing sessions between Nov. 1985 and May 1986. The HCN production rate is well correlated with the total visual magnitude of the comet, indicating that HCN follows the overall gas and dust production. However, comparison of HCN production to the total gas production of the comet indicates that it is a relatively minor consitiuent with 0.1% of the abundance of H2O. Spectra obtained by binning the HCN data with heliocentric distance show that the HCN line width, and thus the parent outflow velocity, increases with decreasing heliocentric distance, and that there is a tendency for the lines to be blue shifted as expected from the observed anisotropic outgassing from the nucleus. There is evidence of day-to-day time variability in the total HCN emission and variations in the HCN hyperfine ratios from their LTE values.

Schloerb, F. Peter↗

NASA NTRS1986

HCN production from comet Halley

The HCN J = 1-0 rotational transition at 3.4 mm wavelength has been detected and has been monitored in comet P/Halley during a total of 56 individual observing sessions between November 18, 1985 and May 11, 1986. The HCN spectra show significant daily variations in total intensity, but the average HCN production rate is well correlated with the visual magnitude of the comet over the range of heliocentric distance observed (between 0.59 and 1.8). Observations of the ratios of the F = 2-1 and F = 1-1 hyperfine components also exhibit significant daily variations but are, in the mean, consistent with the 5:3 ratio expected from the statistical weights of the hyperfine levels. The outflow velocity of the coma, deduced from the HCN linewidths, is 0.87 + or - 0.12 km/s, which is consistent with recent theoretical estimates as well as the measurements of the Giotto spacecraft.

Schloerb, F. Peter↗