Search NASA⌕ Search

Engineering topics

Pryor, Wayne R.

Publications and source records attributed to Pryor, Wayne R..

The Middle Ultraviolet-Visible Spectrum of H2 Excited by Electron Impact

The electron-impact-induced emission spectrum of H2 has been measured in the extended wavelength region 175-530 mm at a spectral resolution of 1.7 mm (FWHM). The laboratory spectra are characterized by underlying H2 (a (sup 3) Sigma(sup +, sub g) to b (sup 3) Sigma(sup +, sub u) continuum emission. together with many strong lines assigned to the radiative decay of the gerade singlet states of H2, and to members of the H Balmer series resulting from dissociative excitation of H2.

James, Geoffrey K.↗

Solar wind latitude variations and multiple scattering from Galileo interplanetary Lyman-alpha observations

The Galileo Ultraviolet Spectrometer Experiment (UVS) obtained a map of the celestial sphere from interplanetary Lyman-alpha (IPLA) on 13, 14 December 1990 during the Earth1 encounter. The Galileo spacecraft was near the downwind interstellar axis during the encounter and the map view directions filled the downwind hemisphere. The ratio between the observation and a single scattering model is attributed to a direct measurement of the multiple scattering correction required to model IPLA in the inner solar system. Analysis of this data set, referred to as an antisun map, shows that the solar wind charge exchange rate with interplanetary gas is 25 percent less over the solar poles than in the ecliptic at solar maximum. A model of the interstellar wind based on the antisun map observation exhibits a number density of atomic hydrogen far from the solar system, inside the heliosphere, of 0.16 +/- 0.05/cu cm.

Ajello, Joseph M.↗

High-phase-angle observations of Neptune at 2650 and 7500 A - Haze structure and particle properties

An analysis is conducted of spatially resolved Voyager 2 Photopolarimeter Subsystem (PPS) observations at 2650 and 7500 A. The continuum absorber that is tropospherically abundant, if confined to the region below the methane haze layer, indicates an optical depth for that layer no greater than 0.8; models in which this optical depth is as large as 3.0 yield too much limb darkening, in the case where the continuum absorber is mixed with both the methane haze and deeper clouds. Tropospheric aerosols are noted to have phase functions with shallow backward lobes.

Pryor, Wayne R.↗

A study of photopolarimeter system UV absorption data on Jupiter, Saturn, Uranus, and Neptune - Implications for auroral haze formation

The present investigation of the dark hazes of Jupiter, Saturn, Uranus, and Neptune on the basis of Voyager 2 UV data notes a geographic correlation between the auroral zones of Jupiter and Saturn and UV-dark polar regions. While the auroral fluxes and penetration depths on Jupiter and Saturn may suffice for a darkening of the polar regions by auroras' action on methane, Uranus and Neptune are found to be bright at all latitudes. In the former case, this brightness is in keeping with auroral electron energies too small to reach the CH4 homopause at which haze production occurs; in the latter case, a UV-dark band exists from 30 deg S to 5 deg N which is probably unrelated to auroral processes.

Pryor, Wayne R.↗

Photometry from Voyager 2 - Initial results from the Neptunian atmosphere, satellites, and rings

Voyager 2 has performed photopolarimetric measurements for the planet, several of its satellites, and its ring system. The Great Dark Spot is noted to appear as a low-albedo region, while the bright companion appear to lie at a higher altitude than the Great Dark Spot. Triton's linear phase coefficients are consistent with a solid-surface object having high reflectivity; its rotational phase curve indicates two major compositional units at its surface. The deficiency of material in Neptune's ring system by comparison with that of Uranus may indicate the absence of a recent moon-shattering event.

Lane, Arthur L.↗