Ultraviolet Spectrometer Observations of Neptune and Triton

  title={Ultraviolet Spectrometer Observations of Neptune and Triton},
  author={A. Lyle Broadfoot and Sushil Atreya and J L Bertaux and Jacques E. Blamont and Alexander J. Dessler and Thomas M. Donahue and William T. Forrester and Doyle Thomas Hall and Floyd Leigh Herbert and Jay B. Holberg and David Hunter and Vladimir A. Krasnopolsky and Susan H. Linick and Jonathan I. Lunine and John C. McConnell and H. Warren Moos and B. R. Sandel and Nicholas M. Schneider and Donald E. Shemansky and G. R. Smith and Darrell F. Strobel and Roger V. Yelle},
  pages={1459 - 1466}
Results from the occultation of the sun by Neptune imply a temperature of 750 � 150 kelvins in the upper levels of the atmosphere (composed mostly of atomic and molecular hydrogen) and define the distributions of methane, acetylene, and ethane at lower levels. The ultraviolet spectrum of the sunlit atmosphere of Neptune resembles the spectra of the Jupiter, Saturn, and Uranus atmospheres in that it is dominated by the emissions of H Lyman α (340 � 20 rayleighs) and molecular hydrogen. The… Expand
On the thermal structure of Triton's thermosphere
The analysis of the Voyager 2 Ultraviolet Spectrometer (UVS) solar occultation data obtained at Triton is consistent with a spherically symmetric, isothermal thermosphere above 400 km at T∞. = 96 K.Expand
Origin of Aurora and Airglow on the Night Side of Neptune
We have examined the latitude-longitude distribution of emissions detected by the Voyager ultraviolet spectrometer on the dark hemisphere of Neptune, The emissions have two significant geographicExpand
Study of planetary atmospheres by absorptive occultations
As a spacecraft observes the setting or rising of the Sun or a star behind the limb of a planet, the absorption spectrum of the upper atmosphere can be observed as a function of height. This powerfulExpand
Infrared Observations of the Neptunian System
Comparison of winds derived from images with the vertical wind shear calculated from the temperature field indicates a general decay of wind speed with height, a phenomenon also observed on the other three giant planets. Expand
Thermal spectroscopy of Neptune: the stratospheric temperature, hydrocarbon abundances, and isotopic ratios
Abstract Portions of Neptune's disk-averaged spectrum were observed from the NASA/Infrared Telescope Facility in 1989 and 1990 with a cryogenic echelle array spectrometer, with resolution of ν/Δν ∼Expand
The atmosphere of Neptune: Results of radio occultation measurements with the Voyager 2 spacecraft
Radio tracking data acquired during Voyager 2's occultation by Neptune have been used to study the thermal structure and composition of Neptune's troposphere and stratosphere. The occultation beganExpand
Detection of CO in Triton's atmosphere and the nature of surface-atmosphere interactions
Context. Triton possesses a thin atmosphere, primarily composed of nitrogen, sustained by the sublimation of surface ices. Aims. We aim at determining the composition of Triton’s atmosphere toExpand
Molecular emissions from the atmospheres of giant planets and comets: Needs for spectroscopic and collision data
Publisher Summary This chapter discusses the emission spectra of the atmospheres of the giant planets and comets. Emphasis is placed on the recent high resolution observations with space probes andExpand
The photochemistry of methane in the atmosphere of Triton
The photochemistry of methane in Triton's atmosphere is driven by approximately equal contributions of solar and local Interstellar medium (LISM) Lyα and in combination with weak vertical mixing, K ∼Expand
Voyager 2 ultraviolet spectrometer occultation observations at Triton have revealed two constituents of the troposphere: CH4 and another absorber visible between 1400 and 1600 A below about 20 kmExpand


Ultraviolet Spectrometer Observations of Uranus
The high temperature of the atmosphere, the small size of Uranus, and the number density of hydrogen atoms in the thermosphere imply an extensive thermal hydrogen corona that reduces the orbital lifetime of ring particles and biases the size distribution toward larger particles. Expand
Extreme Ultraviolet Observations from the Voyager 2 Encounter with Saturn
Combined analysis of helium (584 angstroms) airglow and the atmospheric occultations of the star δ Scorpii imply a vertical mixing parameter in Saturn's upper atmosphere of K (eddy diffusionExpand
The upper atmosphere of Uranus: EUV occultations observed by Voyager 2
Occultation observations of the upper atmosphere of Uranus by the Voyager 2 ultraviolet spectrometer are analyzed. The measurements extend from 0.5 mbar to about 10−6 µbar using the EUV wavelengthsExpand
Overview of the Voyager ultraviolet spectrometry results through Jupiter encounter
The Voyager ultraviolet spectrometers (UVS) have been making almost continuous observations, in the 500-A to 1700-A wavelength range, of sources in the solar system and galaxy since launch in 1977.Expand
Infrared Observations of the Neptunian System
Comparison of winds derived from images with the vertical wind shear calculated from the temperature field indicates a general decay of wind speed with height, a phenomenon also observed on the other three giant planets. Expand
Iue observations of Neptune for H Lyman‐α emission
Neptune has been observed on seven occasions with the International Ultraviolet Explorer Observatory (IUE, Boggess et al. 1978) in an attempt to detect planetary H Ly-α line emission. The observingExpand
EUV emission from Titan's upper atmosphere: Voyager 1 encounter
Analysis of Titan's EUV emission spectra obtained at the Voyager 1 encounter demonstrates that electron impact on N2 above 3600 km accounts for the bulk of the observed emission short of Lyman α. InExpand
The dependence of electroglow on the solar flux
A comparison is made of the observed properties of electroglow on Jupiter, Saturn, and Uranus. It is found that the subsolar electroglow intensity measured by the Voyager Ultraviolet Spectrometer inExpand
The helium abundance of Saturn from Voyager measurements
Voyager radio-occultation and IR spectroscopy measurements are combined to infer an He mole fraction in the upper troposphere of Uranus of 0.152 + or - 0.033; the corresponding mass fraction is Y =Expand
Nitrogen on Triton
Abstract The near-infrared spectrum of Triton is characterized by strong absorption bands of methane, probably in the solid state. An additional absorption band at 2.16 μm is tentatively identifiedExpand