Nitrogen hydrides in the cold envelope of IRAS 16293-2422

被引：59

作者：

Hily-Blant, P. ^{[1
]}

Maret, S. ^{[1
]}

Bacmann, A. ^{[1
,2
]}

Bottinelli, S. ^{[5
]}

Parise, B. ^{[10
]}

Caux, E. ^{[5
]}

Faure, A. ^{[1
]}

Bergin, E. A. ^{[25
]}

Blake, G. A.

Castets, A. ^{[1
]}

Ceccarelli, C. ^{[1
]}

Cernicharo, J. ^{[9
]}

Coutens, A. ^{[5
]}

Crimier, N. ^{[1
,9
]}

Demyk, K. ^{[5
]}

Dominik, C. ^{[12
,13
]}

Gerin, M. ^{[28
]}

Hennebelle, P. ^{[28
]}

Henning, T. ^{[26
]}

Kahane, C. ^{[1
]}

Klotz, A.

Melnick, G. ^{[18
]}

Pagani, L. ^{[7
,8
]}

Schilke, P. ^{[10
,20
]}

Vastel, C. ^{[5
]}

Wakelam, V. ^{[2
]}

Walters, A. ^{[5
]}

Baudry, A. ^{[2
]}

Bell, T.

Benedettini, M. ^{[4
]}

Boogert, A. ^{[3
]}

Cabrit, S. ^{[7
,8
]}

Caselli, P. ^{[6
]}

Codella, C. ^{[11
]}

Comito, C. ^{[10
]}

Encrenaz, P. ^{[7
,8
]}

Falgarone, E. ^{[28
]}

Fuente, A. ^{[14
]}

Goldsmith, P. F. ^{[15
]}

Helmich, F. ^{[16
]}

Herbst, E. ^{[17
]}

Jacq, T. ^{[2
]}

Kama, M. ^{[12
]}

Langer, W. ^{[15
]}

Lefloch, B. ^{[1
]}

Lis, D.

Lord, S. ^{[3
]}

Lorenzani, A. ^{[11
]}

Neufeld, D. ^{[19
]}

Nisini, B. ^{[24
]}

机构：

[1] Univ Grenoble 1, CNRS, Lab Astrophys Grenoble, UMR 5571, Grenoble, France

[2] Univ Bordeaux, Lab Astrophys Bordeaux, CNRS, INSU,UMR 5804, Floirac, France

[3] CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91109 USA

[4] Ist Fis Spazio Interplanetario, INAF, Rome, Italy

[5] Univ Toulouse 3, CNRS, Ctr Etud Spatiale Rayonnements, UMR 5187, F-31062 Toulouse, France

[6] Univ Leeds, Sch Phys & Astron, Leeds, W Yorkshire, England

[7] Observ Paris, CNRS, LERMA, F-75014 Paris, France

[8] Observ Paris, CNRS, UMR 8112, F-75014 Paris, France

[9] CSIC, INTA, Ctr Astrobiol, Madrid, Spain

[10] Max Planck Inst Radioastron, D-5300 Bonn, Germany

[11] INAF Osservatorio Astrofis Arcetri, Florence, Italy

[12] Univ Amsterdam, Astron Inst Anton Pannekoek, Amsterdam, Netherlands

[13] Radboud Univ Nijmegen, Dept Astrophys, IMAPP, NL-6525 ED Nijmegen, Netherlands

[14] IGN Observ Astron Nacl, Alcala De Henares, Spain

[15] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[16] SRON Netherlands Inst Space Res, Groningen, Netherlands

[17] Ohio State Univ, Columbus, OH 43210 USA

[18] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[19] Johns Hopkins Univ, Baltimore, MD USA

[20] Univ Cologne, Inst Phys, Cologne, Germany

[21] Inst Radio Astron Millimetr, Grenoble, France

[22] Leiden Univ, Leiden Observ, Leiden, Netherlands

[23] UCL, Dept Phys & Astron, London, England

[24] Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, Italy

[25] Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA

[26] Max Planck Inst Astron, D-69117 Heidelberg, Germany

[27] Univ Groningen, Kapteyn Astron Inst, NL-9700 AB Groningen, Netherlands

[28] Ecole Normale Super, CNRS, LERMA, UMR 8112, Paris, France

来源：

ASTRONOMY & ASTROPHYSICS | 2010年 / 521卷

关键词：

ISM: abundances; ISM: general; astrochemistry; DISSOCIATIVE RECOMBINATION; PROTOSTAR IRAS16293-2422; INTERSTELLAR CLOUDS; DARK CLOUDS; CHEMISTRY; NH; MOLECULES; N2H+; SPECTROSCOPY; REGIONS;

D O I：

10.1051/0004-6361/201015253

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

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 approximate to 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.

引用

页数：7

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