Showing papers by "Edwin A. Valentijn published in 1997"

First results of ISO-SWS observations of Saturn: Detection of CO2, CH3C2H, C4H2 and tropospheric H2O

Abstract: The spectrum of Saturn has been recorded between 4.5 and 16.0 mu m with the grating mode of the Short-Wavelength Spectrometer (SWS) of ISO. The resolving power is 1500. The main results of this observation are (1) the detection of CO2 CH3C2H and C4H2 in the stratosphere and (2) the detection of H2O in the troposphere. In the 4.5-5.5 mu m range, information is retrieved on the tropospheric composition (NH3, PH3, AsH3, GeH4, CH3D and H2O) down to pressure levels of several bars. Above 7 mu m, the Saturn spectrum probes the upper troposphere and the lower stratosphere, at pressure levels ranging from 0.5 bar to 0.4 mbar. The CH4 emission band at 7.7 mu m and the H-2-He continuum longward of 11 mu m are used to retrieve the thermal profile, which is then used to derive the vertical distributions of minor species: NH3, PH3, CH3D in the troposphere, and C2H2 and C2H6 in the stratosphere. Estimates of the CO2, CH3C2H and C4H2 mean mixing ratios (above the 10-mbar level) are 3 10(-10), 6 10(-10) and 9 10(-11) respectively. The retrieved disk-averaged thermal profile is found to be colder in the stratosphere than the Voyager 1 ingress radio-occultation profile by about 7 K at P = 0.5 mbar, and slightly warmer in the troposphere (about 5 K at 400 mbar and 3 K at 150 mb).

New wavelength determinations of mid-infrared fine-structure lines by Infrared Space Observatory Short Wavelength Spectrometer

Abstract: We report accurate new wavelengths for 29 mid-infrared ionic fine-structure lines, based on observations with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). Our results originate from observations of NGC 7027, NGC 6543, NGC 6302, the Circinus galaxy, Sgr A West, and W51 IRS 2. The obtained accuracies (λ/Δλ) range from 3 × 104 to 1 × 105, depending on instrumental mode and uncertainty in radial velocities.