Water in massive star-forming regions: HIFI observations of W3 IRS5

Chavarría, L.; Herpin, Fabrice; Jacq, T.; Braine, J.; Bontemps, Sylvain; Baudry, A.; Marseille, M.; Tak, van der Floris; Pietropaoli, B.; Wyrowski, F.; Shipman, R.; Frieswijk, W.; Dishoeck, E. F. van; Cernicharo, J.; Bachiller, R.; Benedettini, M.; Benz, A. O.; Bergin, Edwin A.; Bjerkeli, P.; Blake, Geoffrey A.; Bruderer, S.; Caselli, P.; Codella, C.; Daniel, F.; Giorgio, A. M. Di; Dominik, C.; Doty, S. D.; Encrenaz, P.; Fich, M.; Fuente, A.; Giannini, T.; Goicoechea, J. R.; Graauw, Th. de; Hartogh, P.; Helmich, Frank; Herczeg, G. J.; Hogerheijde, M. R.; Johnstone, Doug; Jørgensen, J. K.; Kristensen, L. E.; Larsson, Bengt; Lis, D.; Liseau, R.; McCoey, C.; Melnick, Gary J.; Nisini, B.; Olberg, M.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Santiago-García, J.; Saraceno, P.; Stützki, J.; Szczerba, R.; Tafalla, M.; Tielens, A. G. G. M.; Kempen, T. A. van; Visser, R.; Wampfler, S. F.; Willem, J.; Yıldız, U. A.

doi:10.1051/0004-6361/201015113

Cited by 44 publications

(28 citation statements)

References 30 publications

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“…Thermal evaporation of water ice at about 100 K should produce a hot core water abundance of about 10 −4 (Ceccarelli et al 1996;Rodgers & Charnley 2003). Such abundances are indeed observed for high-mass protostars (van der Tak et al 2006;Chavarría et al 2010;Herpin et al 2012), though not universally (Emprechtinger et al 2013).…”

Section: Introductionmentioning

confidence: 74%

“…Measuring the hot core water abundance in a protostar is not a trivial task, regardless of whether it is a low-or a high-mass source. Shocked gas tends to outshine the quiescent inner envelope (Melnick et al 2000;Chavarría et al 2010;Kristensen et al 2010Kristensen et al , 2012Coutens et al 2012;Emprechtinger et al 2013), so one has to isolate the envelope emission from velocityresolved spectra. Hot core abundances derived from spectrally unresolved data, such as from the Infrared Space Observatory (ISO; Ceccarelli et al 2000;Maret et al 2002), should therefore be treated with caution.…”

Section: Introductionmentioning

confidence: 99%

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Hot Water in the Inner 100 Au of the Class 0 Protostar NGC 1333 Iras2a

Visser

Jørgensen

Kristensen

et al. 2013

ApJ

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Evaporation of water ice above 100 K in the inner few 100 AU of low-mass embedded protostars (the so-called hot core) should produce quiescent water vapor abundances of ∼10 −4 relative to H 2 . Observational evidence so far points at abundances of only a few 10 −6 . However, these values are based on spherical models, which are known from interferometric studies to be inaccurate on the relevant spatial scales. Are hot cores really that much drier than expected, or are the low abundances an artifact of the inaccurate physical models? We present deep velocity-resolved Herschel-HIFI spectra of the 3 12 -3 03 lines of H 16 2 O and H 18 2 O (1097 GHz, E u /k = 249 K) in the low-mass Class 0 protostar NGC1333 IRAS2A. A spherical radiative transfer model with a power-law density profile is unable to reproduce both the HIFI data and existing interferometric data on the H 18 2 O 3 13 -2 20 line (203 GHz, E u /k = 204 K). Instead, the HIFI spectra likely show optically thick emission from a hot core with a radius of about 100 AU. The mass of the hot core is estimated from the C 18 O J = 9-8 and 10-9 lines. We derive a lower limit to the hot water abundance of 2 × 10 −5 , consistent with the theoretical predictions of ∼10 −4 . The revised HDO/H 2 O abundance ratio is 1 × 10 −3 , an order of magnitude lower than previously estimated.

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Section: Introductionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Hot Water in the Inner 100 Au of the Class 0 Protostar NGC 1333 Iras2a

Visser

Jørgensen

Kristensen

et al. 2013

ApJ

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“…Line profiles of H 2 O observed with HIFI show a variety of emission and absorption components that are not resolved by PACS (Chavarría et al 2010;Kristensen et al 2012; van der Tak et al 2013). The only H 2 O lines observed in common by the two instruments within the WISH program are the ground-state transitions: 2 12 − 1 01 at 179.5 µm (1670 GHz) and 2 21 −1 12 at 180.5 µm (1661 GHz), both dominated by absorptions and therefore not optimal to estimate to what extent a complex water profile is diluted at the PACS spectral resolution.…”

Section: Resultsmentioning

confidence: 99%

Far-infrared molecular lines from low- to high-mass star forming regions observed withHerschel

Karska

Herpin

Bruderer

et al. 2014

A&A

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Aims. Our aim is to study the response of the gas-to-energetic processes associated with high-mass star formation and compare it with previously published studies on low-and intermediate-mass young stellar objects (YSOs) using the same methods. The quantified far-IR line emission and absorption of CO, H 2 O, OH, and [O i] reveals the excitation and the relative contribution of different atomic and molecular species to the gas cooling budget. Methods. Herschel/PACS spectra covering 55-190 μm are analyzed for ten high-mass star forming regions of luminosities L bol ∼ 10 4 −10 6 L and various evolutionary stages on spatial scales of ∼10 4 AU. Radiative transfer models are used to determine the contribution of the quiescent envelope to the far-IR CO emission. Results. The close environments of high-mass protostars show strong far-IR emission from molecules, atoms, and ions. Water is detected in all 10 objects even up to high excitation lines, often in absorption at the shorter wavelengths and in emission at the longer wavelengths. CO transitions from J = 14−13 up to typically 29−28 (E u /k B ∼ 580−2400 K) show a single temperature component with a rotational temperature of T rot ∼ 300 K. Typical H 2 O excitation temperatures are T rot ∼250 K, while OH has T rot ∼ 80 K.Far-IR line cooling is dominated by CO (∼75%) and, to a smaller extent, by [O i] (∼20%), which becomes more important for the most evolved sources. H 2 O is less important as a coolant for high-mass sources because many lines are in absorption. Conclusions. Emission from the quiescent envelope is responsible for ∼45-85% of the total CO luminosity in high-mass sources compared with only ∼10% for low-mass YSOs. The highest−J lines (J up ≥ 20) originate most likely in shocks, based on the strong correlation of CO and H 2 O with physical parameters (L bol , M env ) of the sources from low-to high-mass YSOs. The excitation of warm CO described by T rot ∼ 300 K is very similar for all mass regimes, whereas H 2 O temperatures are ∼100 K high for high-mass sources compared with low-mass YSOs. The total far-IR cooling in lines correlates strongly with bolometric luminosity, consistent with previous studies restricted to low-mass YSOs. Molecular cooling (CO, H 2 O, and OH) is ∼4 times greater than cooling by oxygen atoms for all mass regimes. The total far-IR line luminosity is about 10 −3 and 10 −5 times lower than the dust luminosity for the lowand high-mass star forming regions, respectively.

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“…This leads to a typical H 2 O/CO abundance ratio of 0.2-0.5. Figure 2 includes the excited p-H 2 O line for the high-mass YSO W3 IRS5 (Chavarría et al 2010). The profile reveals the same broad and medium-broad components as seen for their low-and intermediate-mass counterparts.…”

Section: Intermediate-mass Ysosmentioning

confidence: 77%

Water in star‐forming regions with Herschel

Kristensen

Dishoeck

2011

Astron Nachr

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The Herschel Space Observatory is well suited to address several important questions in star-and planet formation, as is evident from its first year of operation. This paper focuses on observations of water, a key molecule in the physics and chemistry of star-formation. In the WISH Key Program, a comprehensive set of water lines is being obtained with the HIFI and PACS instruments toward a large sample of well-characterized protostars, covering a wide range of luminosities and evolutionary stages. Lines of H2O, CO and their isotopologues, as well as chemically related hydrides, [O I] and [C II] are observed. Together, the data determine the abundance of water in cold and warm gas, reveal the entire CO ladder up to 4000 K above ground, elucidate the physical processes responsible for the warm gas (passive heating, UV or Xray-heating, shocks), quantify the main cooling agents, and probe dynamical processes associated with forming stars and planets.

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Water in massive star-forming regions: HIFI observations of W3 IRS5

Cited by 44 publications

References 30 publications

Hot Water in the Inner 100 Au of the Class 0 Protostar NGC 1333 Iras2a

Hot Water in the Inner 100 Au of the Class 0 Protostar NGC 1333 Iras2a

Far-infrared molecular lines from low- to high-mass star forming regions observed withHerschel

Water in star‐forming regions with Herschel

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