Water deuterium fractionation in the inner regions of two solar type protostars

Abstract

The [HDO]/[H2O] ratio is a crucial parameter for probing the history of water formation. So far, it has been measured for only three solar type protostars and yielded different results, possibly pointing to a substantially different history in their formation. In the present work, we report new interferometric observations of the HDO 4 2,2 - 4 2,3 line for two solar type protostars, IRAS2A and IRAS4A, located in the NGC1333 region. In both sources, the detected HDO emission originates from a central compact unresolved region. Comparison with previously published interferometric observations of the H218$O31,3-22,0lineshowsthattheHDOandH$_2$Olinesmostlycomefromthesameregion.Anon-LTELVGanalysisoftheHDOandH218$O line emissions, combined with published observations, provides a [HDO]/[H2O] ratio of 0.3 - 8 % in IRAS2A and 0.5 - 3 % in IRAS4A. First, the water fractionation is lower than that of other molecules such as formaldehyde and methanol in the same sources. Second, it is similar to that measured in the solar type protostar prototype, IRAS16293-2422, and, surprisingly enough, larger than that measured in NGC1333 IRAS4B. {The comparison of the measured values towards IRAS2A and IRAS4A with the predictions of our gas-grain model GRAINOBLE gives similar conclusions to those for IRAS 16293, arguing that these protostars {share} a similar chemical history, although they are located in different clouds.

Accepted for publication to ApJL. 6 pages, 2 figures

References in corpus (5)

• First detection of triply-deuterated methanol
• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• Water ice deuteration: a tracer of the chemical history of protostars
• Warm water deuterium fractionation in IRAS 16293-2422 - The high-resolution ALMA and SMA view
• The Abundance, Ortho/Para Ratio, and Deuteration of Water in the High-Mass Star Forming Region NGC 6334 I

Cited by in corpus (27)

• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• The ALMA-PILS survey: Isotopic composition of oxygen-containing complex organic molecules toward IRAS 16293-2422B
• Constraining the abundances of complex organics in the inner regions of solar-type protostars
• Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
• Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores
• Chemical modelling of complex organic molecules with peptide-like bonds in star-forming regions
• Chemo-dynamical deuterium fractionation in the early solar nebula: The origin of water on Earth and in asteroids and comets
• Water in Protoplanetary Disks: Deuteration and Turbulent Mixing
• Water deuteration and ortho-to-para nuclear spin ratio of H2 in molecular clouds formed via the accumulation of HI gas
• Reconstructing the history of water ice formation from HDO/H2O and D2O/HDO ratios in protostellar cores
• The deuterium fractionation of water on solar-system scales in deeply-embedded low-mass protostars
• HD depletion in starless cores
• Deuterated water in the solar-type protostars NGC 1333 IRAS 4A and IRAS 4B
• High D${}_2$O/HDO ratio in the inner regions of the low-mass protostar NGC1333 IRAS2A
• ALMA observations of water deuteration: A physical diagnostic of the formation of protostars
• ALMA observations of doubly deuterated water: Inheritance of water from the prestellar environment
• Interferometric observations of warm deuterated methanol in the inner regions of low-mass protostars
• Chemical modeling of water deuteration in IRAS16293-2422
• Deuterium enrichment of the interstellar grain mantle
• Hot and dense water in the inner 25 AU of SVS13-A
• A high HDO/H${}_2$O ratio in the Class I protostar L1551 IRS5
• The D/H Ratio of Water Ice at Low Temperatures
• Was Earth's water acquired locally during the earliest phases of the Solar System formation?
• Detectability of deuterated water in prestellar cores
• The first interferometric measurements of NH${}_2$D/NH${}_3$ ratio in hot corinos
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IX. Deuterated compounds of H2S in starless cores
• Imaging the water snowline in protostellar envelopes