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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…