Decin L, Justtanont K, De Beck E, Lombaert R, de Koter A, Waters LBFM, et al. Water content and wind acceleration in the envelope around the oxygen-rich AGB star IK Tauri as seen by Herschel/HIFI. Astron. Astrophys.. 2010;521:L4.
Abstract: During their asymptotic giant branch evolution, low-mass stars lose a significant fraction of their mass through an intense wind, enriching the interstellar medium with products of nucleosynthesis. We observed the nearby oxygen-rich asymptotic giant branch star IK Tau using the high-resolution HIFI spectrometer onboard Herschel. We report on the first detection of H216O and the rarer isotopologues H217O and H218O in both the ortho and para states. We deduce a total water content (relative to molecular hydrogen) of $6.6 \times 10^{-5}$, and an ortho-to-para ratio of 3:1. These results are consistent with the formation of H2O in thermodynamical chemical equilibrium at photospheric temperatures, and does not require pulsationally induced non-equilibrium chemistry, vaporization of icy bodies or grain surface reactions. High-excitation lines of 12CO, 13CO, 28SiO, 29SiO, 30SiO, HCN, and SO have also been detected. From the observed line widths, the acceleration region in the inner wind zone can be characterized, and we show that the wind acceleration is slower than hitherto anticipated.
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Bujarrabal V, Alcolea J, Soria-Ruiz R, Planesas P, Teyssier D, Marston AP, et al. Herschel/HIFI observations of high-J CO transitions in the protoplanetary nebula CRL 618. Astron. Astrophys.. 2010;521:L3 (1 to 5).
Abstract: Aims. We aim to study the physical conditions, particularly the excitation state, of the intermediate-temperature gas components in the protoplanetary nebula CRL 618. These components are particularly important for understanding the evolution of the nebula.
Methods. We performed Herschel/HIFI observations of several CO lines in the far-infrared/sub-mm in the protoplanetary nebula CRL 618. The high spectral resolution provided by HIFI allows measurement of the line profiles. Since the dynamics and structure of the nebula is well known from mm-wave interferometric maps, it is possible to identify the contributions of the different nebular components (fast bipolar outflows, double shells, compact slow shell) to the line profiles. The observation of these relatively high-energy transitions allows an accurate study of the excitation conditions in these components, particularly in the warm ones, which cannot be properly studied from the low-energy lines.
Results. The 12CO J = 16–15, 10–9, and 6–5 lines are easily detected in this source. Both 13CO J = 10–9 and 6–5 are also detected. Wide profiles showing spectacular line wings have been found, particularly in 12CO J = 16–15. Other lines observed simultaneously with CO are also shown. Our analysis of the CO high-J transitions, when compared with the existing models, confirms the very low expansion velocity of the central, dense component, which probably indicates that the shells ejected during the last AGB phases were driven by radiation pressure under a regime of maximum transfer of momentum. No contribution of the diffuse halo found from mm-wave data is identified in our spectra, because of its low temperature. We find that the fast bipolar outflow is quite hot, much hotter than previously estimated; for instance, gas flowing at 100 km s-1 must have a temperature higher than ~200 K. Probably, this very fast outflow, with a kinematic age <100 yr, has been accelerated by a shock and has not yet cooled down. The double empty shell found from mm-wave mapping must also be relatively hot, in agreement with the previous estimate.
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Hartogh P, Crovisier J, de Val-Borro M, Bockelée-Morvan D, Biver N, Lis DC, et al. HIFI observations of water in the atmosphere of comet C/2008 Q3 (Garradd). Astron. Astrophys.. 2010;518:L150 (1 to 5).
Abstract: High-resolution far-infrared and sub-millimetre spectroscopy of water lines is an important tool to understand the physical and chemical properties of cometary atmospheres. We present observations of several rotational ortho- and para-water transitions in comet C/2008 Q3 (Garradd) performed with HIFI on Herschel. These observations have provided the first detection of the 212–101 (1669 GHz) ortho and 111–000 (1113 GHz) para transitions of water in a cometary spectrum. In addition, the ground-state transition 110–101 at 557 GHz is detected and mapped. By detecting several water lines quasi-simultaneously and mapping their emission we can constrain the excitation parameters in the coma. Synthetic line profiles are computed using excitation models which include excitation by collisions, solar infrared radiation, and radiation trapping. We obtain the gas kinetic temperature, constrain the electron density profile, and estimate the coma expansion velocity by analyzing the map and line shapes. We derive water production rates of 1.7–2.8 × 1028 s-1 over the range rh = 1.83–1.85 AU.
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Käufl HU, Rothermal H, Drapatz S. Investigation of the Martian atmosphere by 10 micron heterodyne spectroscopy. A&A. 1984;136:319–25.
Keywords: astronomical spectroscopy, atmospheric composition, infrared astronomy, mars atmosphere, spectral line width, carbon dioxide concentration, nonequilibrium thermodynamics, optical heterodyning, planetary radiation, mars, atmosphere, spectroscopy, atmosphere, carbon dioxide, altitude, kinetics, rotation, thermal properties, temperature, emissions, intensity, models, data, spectra
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Rothermel H, Käufl HU, Schrey U, Drapatz S. Thermal structure of the Martian mesosphere. A&A. 1988;196:296–300.
Keywords: atmospheric temperature, carbon dioxide, infrared spectroscopy, mars atmosphere, mesosphere, emission spectra, line spectra, spatial resolution, mars, atmosphere, mesosphere, structure, thermal properties, spectra, spectroscopy, earth-based observations, temperature, patterns, infrared, polar regions, wavelengths, equipment, procedure, carbon dioxide, emissions
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