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Ortho-to-Para Ratio in Interstellar Water on the Sightline toward Sagittarius B2(N)
Bergin, Edwin A.; van Dishoeck, Ewine F.; Lis, Dariusz C. +1 more
The determination of the water ortho-to-para ratio (OPR) is of great interest for studies of the formation and thermal history of water ices in the interstellar medium and protoplanetary disk environments. We present new Herschel observations of the fundamental rotational transitions of ortho- and para-water on the sightline toward Sagittarius B2(…
Neutral and Ionized Hydrides in Star-Forming Regions. Observations with Herschel/HIFI
van Dishoeck, Ewine F.; Benz, Arnold O.; Wampfler, Susanne F. +2 more
The cosmic abundance of hydrides depends critically on high-energy UV, X-ray, and particle irradiation. Here we study hydrides in star-forming regions where irradiation by the young stellar object can be substantial, and density and temperature can be much enhanced over interstellar values. Lines of OH, CH, NH, and SH and their ions OH+, CH+, NH+,…
Ortho/Para Ratio of H2O+ Toward Sagittarius B2(M) Revisited
Bergin, Edwin A.; Lis, Dariusz C.; Schilke, Peter +2 more
The HIFI instrument aboard the Herschel satellite has allowed the observation and characterization of light hydrides, the building blocks of interstellar chemistry. In this article, we revisit the ortho/para ratio for H2O+ toward the Sgr B2(M) cloud core. The line of sight toward this star forming region passes through several spiral arms and the …
Determination of the Ortho to Para Ratio of H2Cl+ and H2O+ from Submillimeter Observations
Kramer, Carsten; Le Petit, Franck; Godard, Benjamin +9 more
The opening of the submillimeter sky with the Herschel Space Observatory has led to the detection of new interstellar molecular ions, H2O+, H2Cl+, and HCl+, which are important intermediates in the synthesis of water vapor and hydrogen chloride. In this paper, we report new observations of H2O+ and H2Cl+ performed with both Herschel and ground-bas…
On the State of Water Ice on Saturn's Moon Titan and Implications to Icy Bodies in the Outer Solar System
Jewitt, David; Kaiser, Ralf I.; Zheng, Weijun
The crystalline state of water ice in the Solar System depends on the temperature history of the ice and the influence of energetic particles to which it has been exposed. We measured the infrared absorption spectra of amorphous and crystalline water ice in the 10-50 K and 10-140 K temperature ranges, respectively, and conducted a systematic exper…
Infrared Spectra of C2H6, C2H4, C2H2, and CO2 Aerosols Potentially Formed in Titan's Atmosphere
Wang, Chia C.; Signorell, Ruth; Zielke, Philipp +2 more
Pure and mixed aerosols of ethane, ethylene, acetylene and carbon dioxide were generated in a collisional cooling cell and characterized by Fourier transform infrared spectroscopy between 600 and 4000 cm-1. Pure ethane, pure ethylene, and mixed ethane/ethylene initially form supercooled liquid droplets, which over time crystallize to their stable …
12C/13C Ratio in Ethane on Titan and Implications for Methane's Replenishment
Nixon, Conor A.; Jennings, Donald E.; Bjoraker, Gordon L. +6 more
The 12C/13C abundance ratio in ethane in the atmosphere of Titan has been measured at 822 cm-1 from high spectral resolution ground-based observations. The value, 89(8), coincides with the telluric standard and also agrees with the ratio seen in the outer planets. It is almost identical to the result for ethane on Titan found by the composite infr…