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相关论文: Water in massive star-forming regions: HIFI observ…

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During the embedded phase of pre-main sequence stellar evolution, a disk forms from the dense envelope while an accretion-driven outflow carves out a cavity within the envelope. Highly excited H2O emission in spatially unresolved…

Understanding water deuterium fractionation is important for constraining the mechanisms of water formation in interstellar clouds. Observations of HDO and H$_2^{18}$O transitions were carried out towards the high-mass star-forming region…

Water is present during all stages of star formation: as ice in the cold outer parts of protostellar envelopes and dense inner regions of circumstellar disks, and as gas in the envelopes close to the protostars, in the upper layers of…

太阳与恒星天体物理 · 物理学 2015-06-04 Magnus V. Persson , Jes K. Jørgensen , Ewine F. van Dishoeck

Water is a very abundant molecule in star-forming regions. Its deuterium fractionation is an important tool for understanding its formation and evolution during the star and planet formation processes. While the HDO/H$_2$O ratio has been…

The cosmic abundance of hydrides depends critically on high-energy UV, X-ray, and particle irradiation. Here we study hydrides in star-forming regions where irradiation by the young stellar object can be substantial, and density and…

太阳与恒星天体物理 · 物理学 2015-06-17 Arnold O. Benz , Simon Bruderer , Ewine F. van Dishoeck , Pascal Staeuber , Susanne F. Wampfler

We present a systematic survey of multiple velocity-resolved H$_2$O spectra using Herschel/HIFI towards nine nearby actively star forming galaxies. The ground-state and low-excitation lines (E$_{\rm up}\,\le 130\,{\rm K}$) show profiles…

Observational evidence for inflowing motions in massive star forming regions has been extremely rare. We have made a spectroscopic survey of a sample of 28 massive star forming cores associated with water masers. An optically thick line of…

天体物理学 · 物理学 2009-11-10 Jingwen Wu , Neal J. Evans

We report the results of observations of ten rotational transitions of water vapor toward the carbon-rich AGB (asymptotic giant branch) star IRC+10216 (CW Leonis), carried out with Herschel's HIFI instrument. Each transition was securely…

We report ISO-LWS far infrared observations of CO, water and oxygen lines towards the protobinary system IRAS4 in the NGC1333 cloud. We detected several water, OH, CO rotational lines, and two [OI] and [CII] fine structure lines. Given the…

天体物理学 · 物理学 2007-05-23 S. Maret , C. Ceccarelli , E. Caux , A. G. G. M. Tielens , A. Castets

We aimed to measure the H2O and dust production rates in C/2006 W3 (Christensen) with the Herschel Space Observatory at a heliocentric distance of ~ 5 AU. We have searched for emission in the H2O and NH3 ground-state rotational transitions…

High-resolution images of the hypercompact HII regions (HCHII) in W3 IRS 5 taken with the Very Large Array (VLA) at 1.3 and 0.7 cm are presented. Four HCHII regions were detected with sufficient signal-to-noise ratios to allow the…

天体物理学 · 物理学 2009-11-10 T. L. Wilson , D. A. Boboltz , R. A. Gaume , S. T. Megeath

Using NASA's Submillimeter Wave Astronomy Satellite (SWAS) we have examined the production of water in quiescent and shocked molecular gas through a survey of the 556.936 GHz transition of ortho-H2O in the NGC 1333 molecular core. These…

天体物理学 · 物理学 2009-11-07 Edwin A. Bergin , Michael J. Kaufman , Gary J. Melnick , Ronald L. Snell , John E. Howe

We have modeled the emission of H2O rotational lines from the extreme C-rich star IRC+10216. Our treatment of the excitation of H2O emissions takes into account the excitation of H2O both through collisions, and through the pumping of the…

天体物理学 · 物理学 2009-11-13 Eduardo González-Alfonso , David A. Neufeld , Gary J. Melnick

The HIFI instrument on board the Herschel Space Observatory has been used to observe interstellar nitrogen hydrides along the sight-line towards G10.6-0.4 in order to improve our understanding of the interstellar chemistry of nitrogen. We…

Observations at mid-infrared (4.8-17.65 um) and radio (0.7-1.3 cm) wavelengths are used to constrain the structure of the high-mass star-forming region W3 IRS5 on 0.1'' (200 AU) scales. Two bright mid-infrared sources are detected, as well…

天体物理学 · 物理学 2009-11-10 F. F. S. van der Tak , P. G. Tuthill , W. C. Danchi

Molecular outflows powered by young protostars strongly affect the kinematics and chemistry of the natal molecular cloud through strong shocks resulting in substantial modifications of the abundance of several species. As part of the…

We present in this paper the results of high spectral resolution ($R$=88,100) spectroscopy at 4.7 $\mu$m with iSHELL/IRTF of hot molecular gas close to the massive binary protostar W3 IRS5. The binary was spatially resolved and the spectra…

星系天体物理 · 物理学 2022-08-31 Jialu Li , Adwin Boogert , Andrew G. Barr , Alexander G. G. M. Tielens

The HDO/H2O abundance ratio is thought to be a key diagnostic on the evolution of water during the star- and planet-formation process and thus on its origin on Earth. We here present millimeter-wavelength high angular resolution…

太阳与恒星天体物理 · 物理学 2015-05-20 Jes K. Jorgensen , Ewine F. van Dishoeck

Herschel-HIFI spectra of H2O towards low-mass protostars show a distinct velocity component not seen in observations from the ground of CO or other species. The aim is to characterise this component in terms of excitation conditions and…

太阳与恒星天体物理 · 物理学 2015-06-16 L. E. Kristensen , E. F. van Dishoeck , A. O. Benz , S. Bruderer , R. Visser , S. F. Wampfler

The HDO/H2O ratio is a powerful diagnostic to understand the evolution of water from the first stages of star formation to the formation of planets and comets. Our aim is to determine precisely the abundance distribution of HDO towards the…