Herschel Far-Infrared Spectral-mapping of Orion BN/KL Outflows: Spatial distribution of excited CO, H2O, OH, O and C+ in shocked gas

Autor: José Cernicharo, Pierre Encrenaz, Edwin A. Bergin, Roland Vavrek, S. Cuadrado, M. Etxaluze, Javier R. Goicoechea, David A. Neufeld, Gary J. Melnick, Edward Polehampton, L. Chavarria
Přispěvatelé: Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique, Université Paris Diderot - Paris 7 (UPD7), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, École normale supérieure - Paris (ENS Paris), Smithsonian Institution-Harvard University [Cambridge], Ministerio de Ciencia e Innovación (España), Ministerio de Economía y Competitividad (España)
Rok vydání: 2014
Předmět:
Zdroj: The Astrophysical Journal
The Astrophysical Journal, 2015, 799 (1), pp.102. ⟨10.1088/0004-637X/799/1/102⟩
The Astrophysical Journal, American Astronomical Society, 2015, 799 (1), pp.102. ⟨10.1088/0004-637X/799/1/102⟩
Astrophysical Journal
Artículos CONICYT
CONICYT Chile
instacron:CONICYT
Digital.CSIC. Repositorio Institucional del CSIC
instname
ISSN: 0004-637X
1538-4357
DOI: 10.48550/arxiv.1411.2930
Popis: We present ~2'x2' spectral-maps of Orion BN/KL outflows taken with Herschel at ~12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H2 shocked regions "Peak 1" and "Peak 2" from that of the Hot Core and ambient cloud. We analyze the ~54-310um spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of 12CO (up to J=48-47), H2O, OH, 13CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L(FIR)~5x10^{-3} ratio and a plethora of far-IR H2O emission lines. The high-J CO and OH lines are a factor ~2 brighter toward Peak 1 whereas several excited H2O lines are ~50% brighter toward Peak 2. A simplified non-LTE model allowed us to constrain the dominant gas temperature components. Most of the CO column density arises from Tk~200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H2O/CO~10^{-2} abundance ratio. In addition, the very excited CO (J>35) and H2O lines reveal a hotter gas component (Tk~2500 K) from faster (v_S>25 km/s) shocks that are able to sputter the frozen-out H2O and lead to high H2O/CO>~1 abundance ratios. The H2O and OH luminosities cannot be reproduced by shock models that assume high (undepleted) abundances of atomic oxygen in the preshock gas and/or neglect the presence of UV radiation in the postshock gas. Although massive outflows are a common feature in other massive star-forming cores, Orion BN/KL seems more peculiar because of its higher molecular luminosities and strong outflows caused by a recent explosive event.
21 pages, 11 figures. Accepted for publication in ApJ (english not edited)
Databáze: OpenAIRE
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