Helmut Feuchtgruber

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The atmospheres of the giant planets are reducing, being mainly composed of hydrogen, helium and methane. But the rings and icy satellites that surround these planets, together with the flux of interplanetary dust, could act as important sources of oxygen, which would be delivered to the atmospheres mainly in the form of water ice or silicate dust. Here we(More)
We present the results of the Infrared Space Observatory Short Wavelength Spectrometer (ISO-SWS) observations of Jupiter related to ammonia. We focus on two spectral regions; the first one (the 10-μm region), ranging from 9.5 to 11.5 μm, probes atmospheric levels between 1 and 0.2 bar, while the second one (the 5-μm window), ranging from 4.8 to 5.5 μm,(More)
The laboratory wavelength calibration of the SWS has been succesfully transferred to the in orbit situation. The achieved accuracies for the grating sections are = 10000. Any remaining errors in the wavelength scale are dominated by uncertainties of the relative position of the target in the 14 20 wide slits. The grating spectral profile is very well(More)
We have analysed the ISO-SWS spectrum of Jupiter in the 12–16 μm range, where several hydrocarbons exhibit rovibrational bands. Using temperature information from the methane and hydrogen emissions, we derive the mixing ratios (q) of acetylene and ethane at two independent pressure levels. For acetylene, we find q = (8.9 −0.6) × 10−7 at 0.3 mbar and q =(More)
We present mid-infrared ISO-SWS observations of the fine-structure emissions and the recombination lines Brα and Brβ, in a sample of 112 Galactic H II regions and 37 nearby extra-galactic H II regions in the LMC, SMC, and M33. We selected our sources from archival ISO-SWS data as those showing prominent [Ne II]12.8µm or [Ne III]15.6µm emissions. The(More)
Observations with the Short Wavelength Spectrometer (SWS) onboard the Infrared Space Observatory (ISO) have led to the first unambiguous detection of HD in the atmospheres of Uranus and Neptune, from its R(2) rotational line at 37.7 μm. Using S(0) and S(1) quadrupolar lines of H2 at 28.2 and 17.0 μm as atmospheric thermometers, we derive D/H ratios of 5.5((More)
We report new observations of the far infrared and submillimeter water vapor emission of NML Cygnus based on data gathered with the Infrared Space Observatory and the Submillimeter Wave Astronomy Satellite. We compare the emission from NML Cyg to that previously published for VY CMa and W Hya in an attempt to establish the validity of recently proposed(More)
The detection of circumstellar water vapour around the ageing carbon star IRC +10216 challenged the current understanding of chemistry in old stars, because water was predicted to be almost absent in carbon-rich stars. Several explanations for the water were postulated, including the vaporization of icy bodies (comets or dwarf planets) in orbit around the(More)
We present a 2.4–45 m spectrum of the center of our Galaxy obtained with the Short Wavelength Spectrometer (SWS) on board ISO. The wide range of ionic fine structure lines observed yields an average effective temperature for the ionizing stars of 35000 K, with a small contribution of significantly hotter stars, consistent with ageing of an active period of(More)
First detections of thermal water vapor absorption lines have been made toward Orion IRc2 using the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). Grating spectra covering wavelengths 25–45 μm yield 19 pure rotational lines, originating from energy levels 200–750 K above ground. Fabry-Perot spectra of 5 transitions(More)