Herschel-HIFI observations of high-J CO lines in the NGC 1333 low-mass star-forming region

U. A. Yildiz , E. F. van Dishoeck , L. E. Kristensen , R. Visser , J. K. Jørgensen , G. J. Herczeg , T. A. van Kempen , M. R. Hogerheijde , S. D. Doty , A. O. Benz , S. Bruderer , S. F. Wampfler , E. Deul , R. Bachiller (1) , Alain Baudry (2, 3, 4, 5) , M. Benedettini (1) , E. Bergin , P. Bjerkeli , G. A. Blake (6) , Sylvain Bontemps (2, 3, 4, 5) , J. Braine (2, 3, 4, 5) , P. Caselli (7) , J. Cernicharo (8) , C. Codella (1) , F. Daniel , A. M. Di Giorgio , C. Dominik (9) , P. Encrenaz (10) , M. Fich , A. Fuente (1) , T. Giannini , J. R. Goicoechea (10) , Th. de Graauw , F. Helmich (1) , Fabrice Herpin (2, 3, 4, 5) , T. Jacq (2, 3, 4, 5) , D. Johnstone , B. Larsson (1) , D. Lis (1) , R. Liseau , F. -C. Liu , M. Marseille (2, 3, 4, 5, 11) , C. Mccoey , G. Melnick (1) , D. Neufeld (1) , B. Nisini (12) , M. Olberg (13) , B. Parise (14) , J. C. Pearson , R. Plume , C. Risacher (15) , J. Santiago-Garcia , P. Saraceno (16) , R. Shipman , M. Tafalla , A. G. G. M. Tielens (11) , F. van Der Tak (1) , F. Wyrowski (17) , P. Dieleman , W. Jellema , V. Ossenkopf (1) , R. Schieder , J. Stutzki (1)

1 LAOG - Laboratoire d'Astrophysique de Grenoble
2 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
3 OASU - Observatoire aquitain des sciences de l'univers
4 UB - Université Sciences et Technologies - Bordeaux 1
5 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
6 LOCIE - LabOratoire proCédés énergIe bâtimEnt
7 OAA - INAF - Osservatorio Astrofisico di Arcetri
8 CSIC - Centro de Investigaciones Biológicas
9 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
10 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
11 SRON - SRON Netherlands Institute for Space Research
12 OAR - INAF - Osservatorio Astronomico di Roma
13 Onsala Space Observatory
14 CESR - Centre d'étude spatiale des rayonnements
15 ESO
16 IFSI - Istituto di Fisica dello Spazio Interplanetario
17 MPIFR - Max-Planck-Institut für Radioastronomie

Herschel-HIFI observations of high-J lines (up to J_u=10) of 12CO, 13CO and C18O are presented toward three deeply embedded low-mass protostars, NGC 1333 IRAS 2A, IRAS 4A, and IRAS 4B, obtained as part of the Water In Star-forming regions with Herschel (WISH) key program. The spectrally-resolved HIFI data are complemented by ground-based observations of lower-J CO and isotopologue lines. The 12CO 10-9 profiles are dominated by broad (FWHM 25-30 km s^-1) emission. Radiative transfer models are used to constrain the temperature of this shocked gas to 100-200 K. Several CO and 13CO line profiles also reveal a medium-broad component (FWHM 5-10 km s^-1), seen prominently in H2O lines. Column densities for both components are presented, providing a reference for determining abundances of other molecules in the same gas. The narrow C18O 9-8 lines probe the warmer part of the quiescent envelope. Their intensities require a jump in the CO abundance at an evaporation temperature around 25 K, thus providing new direct evidence for a CO ice evaporation zone around low-mass protostars.

Mots clés: Astrophysics; Solar and Stellar Astrophysics

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]; Astrophysique stellaire et solaire [astro-ph.SR]

U. A. Yildiz, E. F. van Dishoeck, L. E. Kristensen, R. Visser, J. K. Jørgensen, et al.. Herschel-HIFI observations of high-J CO lines in the NGC 1333 low-mass star-forming region. Astronomy and Astrophysics - A&A, 2010, 521, pp.L40. ⟨10.1051/0004-6361/201015119⟩. ⟨hal-00521341⟩