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Author (up) de Graauw, T.; Caux, E.; Guesten, R.; Helmich, F.; Pearson, J.; Phillips, T. G.; Schieder, R.; Tielens, X.; Saraceno, P.; Stutzki, J.; Wafelbakker, C. K.; Whyborn, N. D.
Title The Herschel-heterodyne instrument for the far-infrared (HIFI) Type Conference Article
Year 2005 Publication Bulletin of the American Astronomical Society Abbreviated Journal
Volume Issue Pages 1219
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Bulletin of the American Astronomical Society Abbreviated Series Title
Series Volume 37 Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number ref2005AAS...207.3503D Serial 420
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Author (up) Maret, S.; Bacmann, A.; Bottinelli, S.; Parise, B.; Caux, E.; Faure, A.; Bergin, E. A.; Blake, G. A.; Castets, A.; Ceccarelli, C.; Cernicharo, J.; Coutens, A.; Crimier, N.; Demyk, K.; Dominik, C.; Gerin, M.; Hennebelle, P.; Henning, T.; Kahane, C.; Klotz, A.; Melnick, G.; Pagani, L.; Schilke, P.; Vastel, C.; Wakelam, V.; Walters, A.; Baudry, A.; Bell, T.; Benedettini, M.; Boogert, A.; Cabrit, S.; Caselli, P.; Codella, C.; Comito, C.; Encrenaz, P.; Falgarone, E.; Fuente, A.; Goldsmith, P. F.; Helmich, F.; Herbst, E.; Jacq, T.; Kama, M.; Langer, W.; Lefloch, B.; Lis, D.; Lord, S.; Lorenzani, A.; Neufeld, D.; Nisini, B.; Pacheco, S.; Phillips, T.; Salez, M.; Saraceno, P.; Schuster, K.; Tielens, X.; van der Tak, F.; van der Wiel, M. H. D.; Viti, S.; Wyrowski, F.; Yorke, H.
Title Nitrogen hydrides in the cold envelope of IRAS 16293-2422 Type Journal Article
Year 2010 Publication Astron. Astrophys. Abbreviated Journal
Volume 521 Issue Pages L52
Keywords HEB mixer applications, HIFI, Herschel, ISM: abundances / ISM: general / astrochemistry
Abstract Nitrogen is the fifth most abundant element in the Universe, yet the gas-phase chemistry of N-bearing species remains poorly understood. Nitrogen hydrides are key molecules of nitrogen chemistry. Their abundance ratios place strong constraints on the production pathways and reaction rates of nitrogen-bearing molecules. We observed the class 0 protostar IRAS 16293-2422 with the heterodyne instrument HIFI, covering most of the frequency range from 0.48 to 1.78 THz at high spectral resolution. The hyperfine structure of the amidogen radical o-NH2 is resolved and seen in absorption against the continuum of the protostar. Several transitions of ammonia from 1.2 to 1.8 THz are also seen in absorption. These lines trace the low-density envelope of the protostar. Column densities and abundances are estimated for each hydride. We find that NH:NH2:NH3 â‰<2c6> 5:1:300. Dark clouds chemical models predict steady-state abundances of NH2 and NH3 in reasonable agreement with the present observations, whilst that of NH is underpredicted by more than one order of magnitude, even using updated kinetic rates. Additional modelling of the nitrogen gas-phase chemistry in dark-cloud conditions is necessary before having recourse to heterogen processes.
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Language Summary Language Original Title
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Notes Approved no
Call Number Serial 1094
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