Ortho-to-para ratio of interstellar heavy water

C. Vastel; C. Ceccarelli; E. Caux; A. Coutens; J. Cernicharo; S. Bottinelli; K. Demyk; A. Faure; L. Wiesenfeld; Y. Scribano; A. Bacmann; P. Hily-Blant; S. Maret; A. Walters; E. A. Bergin; G. A. Blake; A. Castets; N. Crimier; C. Dominik; P. Encrenaz; M. Gérin; P. Hennebelle; C. Kahane; A. Klotz; G. Melnick; L. Pagani; B. Parise; P. Schilke; Valentine Wakelam; Alain Baudry; T. Bell; M. Benedettini; A. Boogert; S. Cabrit; P. Caselli; C. Codella; C. Comito; E. Falgarone; A. Fuente; P. F. Goldsmith; F. Helmich; T. Henning; E. Herbst; T. Jacq; M. Kama; W. Langer; B. Lefloch; D. Lis; S. Lord; A. Lorenzani; D. Neufeld; B. Nisini; S. Pacheco; J. Pearson; T. Phillips; M. Salez; P. Saraceno; K. Schuster; X. Tielens; F. van der Tak; M. H. D. van der Wiel; S. Viti; F. Wyrowski; H. Yorke; Ph. Cais; J. M. Krieg; M. Olberg; L. Ravera

HAL: hal-00633418, version 1

arXiv: 1007.4410

ADS Bibliographic id: 2010A&A...521L..31V

DOI: 10.1051/0004-6361/201015101

Detailed view

Export this paper

Astronomy and Astrophysics 521 (2010) L31

Ortho-to-para ratio of interstellar heavy water

C. Vastel ^1, 2, C. Ceccarelli ³, E. Caux ^1, 2, A. Coutens ³, J. Cernicharo ⁴, S. Bottinelli ⁵, K. Demyk ³, A. Faure ³, L. Wiesenfeld ³, Y. Scribano, A. Bacmann ^{3, 6, 7, 8, 9}, P. Hily-Blant ³, S. Maret ³, A. Walters ³, E. A. Bergin ¹⁰, G. A. Blake ¹¹, A. Castets ³, N. Crimier ³, C. Dominik ¹², P. Encrenaz ¹³, M. Gérin ^13, 14, P. Hennebelle ³, C. Kahane ³, A. Klotz ^5, 15, G. Melnick ³, L. Pagani ¹³, B. Parise ^5, 16, P. Schilke ^17, 18, Valentine Wakelam ^{6, 7, 8, 9}, Alain Baudry ^{6, 7, 8, 9, 19}, T. Bell ³, M. Benedettini ³, A. Boogert ³, S. Cabrit ¹³, P. Caselli ^20, 21, 22, C. Codella ³, C. Comito ¹⁸, E. Falgarone ¹⁴, A. Fuente ³, P. F. Goldsmith, F. Helmich ³, T. Henning ²³, E. Herbst ^24, 25, T. Jacq ^{6, 7, 8, 9}, M. Kama ³, W. Langer ³, B. Lefloch ³, D. Lis ³, S. Lord ³, A. Lorenzani ²⁶, D. Neufeld ³, B. Nisini ²⁷, S. Pacheco ³, J. Pearson ³, T. Phillips ³, M. Salez ³, P. Saraceno ²⁸, K. Schuster ³, X. Tielens ³, F. van der Tak ³, M. H. D. van der Wiel, S. Viti ³, F. Wyrowski ²⁹, H. Yorke ³, Ph. Cais ^{6, 7, 8, 9}, J. M. Krieg, M. Olberg ³⁰, L. Ravera ⁵

(2010-10)

Context. Despite the low elemental deuterium abundance in the Galaxy, enhanced molecular D/H ratios have been found in the environments of low-mass star-forming regions, and in particular the Class 0 protostar IRAS 16293-2422. Aims: The CHESS (Chemical HErschel Surveys of Star forming regions) key program aims to study the molecular complexity of the interstellar medium. The high sensitivity and spectral resolution of the Herschel/HIFI instrument provide a unique opportunity to observe the fundamental 11,1-00,0 transition of the ortho-D2O molecule, which is inaccessible from the ground, and determine the ortho-to-para D2O ratio. Methods: We detected the fundamental transition of the ortho-D2O molecule at 607.35 GHz towards IRAS 16293-2422. The line is seen in absorption with a line opacity of 0.62 ± 0.11 (1σ). From the previous ground-based observations of the fundamental 11,0-10,1 transition of para-D2O seen in absorption at 316.80 GHz, we estimate a line opacity of 0.26 ± 0.05 (1σ). Results: We show that the observed absorption is caused by the cold gas in the envelope of the protostar. Using these new observations, we estimate for the first time the ortho-to-para D2O ratio to be lower than 2.6 at a 3σ level of uncertainty, which should be compared with the thermal equilibrium value of 2:1. Herschel is an ESA space observatory with science instruments provided by European-led principal Investigator consortia and with important participation from NASA.

1:	CNRS INSU, UMR 5187, F-31028 Toulouse 4, France

	UMR 5187 Toulouse

2:	Univ Toulouse UPS, Ctr Etud Spatiale Rayonnements, F-31062 Toulouse 9, France

	Centre Etud Spatiale Rayonnements Toulouse

3:	Laboratoire d'Astrophysique de Grenoble (LAOG)

	CNRS : UMR5571 – OSUG – INSU – Université Joseph Fourier - Grenoble I

4:	Ctr Astrobiol CSIC INTA, Lab Astrofis Mol, Madrid 28850, Spain

	Ctr Astrobiol CSIC INTA, Lab Astrofis Mol, Madrid

5:	Centre d'étude spatiale des rayonnements (CESR)

	CNRS : UMR5187 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III

6:	Laboratoire d'Astrophysique de Bordeaux (LAB)

	CNRS : UMR5804 – INSU – Université Sciences et Technologies - Bordeaux I

7:	Observatoire aquitain des sciences de l'univers (OASU)

	CNRS : UMS2567 – INSU – Université Sciences et Technologies - Bordeaux I

8:	Université Sciences et Technologies - Bordeaux 1

	Université Sciences et Technologies - Bordeaux I

9:	Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB)

	CNRS : UMR5804 – INSU – Université Sciences et Technologies - Bordeaux I

10:	Department of Astronomy

	University of Michigan

11:	Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE)

	Université de Savoie – CNRS : FRE3220

12:	Astronomical Institute "Anton Pannekoek''

	University of Amsterdam

13:	Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA)

	CNRS : UMR8112 – INSU – Observatoire de Paris – Université Pierre et Marie Curie [UPMC] - Paris VI – Université de Cergy Pontoise – Ecole normale supérieure de Paris - ENS Paris

14:	Laboratoire de Radio Astronomie de l'ENS (LRA)

	CNRS : FRE2460 – Observatoire de Paris

15:	Observatoire de Haute-Provence (OHP)

	CNRS : USR2207 – INSU – Université de Provence - Aix-Marseille I

16:	Centre d'Etude Spatiale des Rayonnements

	Aucune

17:	Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany

	Univ Cologne, Inst Phys 1

18:	Max Planck Inst Radioastron, D-53121 Bonn, Germany

	Max Planck Inst Radioastronomy

19:	European Southern Observatory (ESO)

	ESO

20:	Osservatorio Astrofisico di Arcetri (INAF)

	Osservatorio Astrofisico di Arcetri

21:	Osservatorio di arcetri (INAF)

	INFN

22:	Osservatorio Astrofisico di Arcetri (INAF)

	INFN

23:	Max-Planck-Institut für Astronomie (MPIA)

	Max-Planck-Institut

24:	Ohio State Univ, Dept Phys, Columbus, OH 43210 USA

	Ohio State Univ, Dept Phys, Columbus

25:	Ohio State Univ, Dept Astron & Chem, Columbus, OH 43210 USA

	Ohio State Univ, Dept Astron & Chem, Columbus

26:	Osservatorio Astrofisico di Arcetri

	INAF

27:	Osservatorio di Astrofisica di Roma (OAR)

	INAF

28:	Interplanetary Space Physics Institute (IFSI) (IFSI-INAF)

	Interplanetary Space Physics Institute

29:	Max-Planck-Institut für Radioastronomie (MPIFR)

	Max-Planck-Institut

30:	Onsala Space Observatory

	Onsala Space Observatory

Research team: AMOR 2010
FORMATION STELLAIRE 2010

Subject

Sciences of the Universe/Astrophysics/Galactic Astrophysics

Physics/Astrophysics/Galactic Astrophysics

Keyword(s): astrochemistry – ISM: molecules – submillimeter: ISM – ISM: abundances – molecular processes – line: identification

Fulltext link:

http://fr.arXiv.org/abs/1007.4410


hal-00633418, version 1
http://hal.archives-ouvertes.fr/hal-00633418
oai:hal.archives-ouvertes.fr:hal-00633418
From: Laurent Pagani <>
Submitted on: Tuesday, 18 October 2011 14:45:34
Updated on: Wednesday, 7 March 2012 09:29:42