The ALMA-PILS survey: Formaldehyde deuteration in warm gas on small scales toward IRAS 16293-2422 B

Abstract

[abridged] The enhanced degrees of deuterium fractionation observed in envelopes around protostars demonstrate the importance of chemistry at low temperatures, relevant in pre- and protostellar cores. formaldehyde is an important species in the formation of methanol and more complex molecules. Here, we present the first study of formaldehyde deuteration on small scales around the prototypical low-mass protostar IRAS 16293-2422 using high spatial and spectral resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations. Numerous isotopologues of formaldehyde are detected, among them H${}_2$C${}^{17}$O, and D${}_2^{13}$CO for the first time in the ISM. The large range of upper energy levels covered by the HDCO lines help constrain the excitation temperature to 106$\pm$13 K. Using the derived column densities, formaldehyde shows a deuterium fractionation of HDCO/H${}_2$CO=6.5$\pm$1%, D${}_2$CO/HDCO=12.8${}_{-4.1}^{+3.3}$%, and D${}_2$CO/H${}_2$CO=0.6(4)$\pm$0.1%. The isotopic ratios derived are ${}^{16}$O/${}^{18}$O=805, ${}^{18}$O/${}^{17}$O=3.2 and ${}^{12}$C/${}^{13}$C=56. The HDCO/H${}_2$CO ratio is lower than found in previous studies, highlighting the uncertainties involved in interpreting single dish observations of the inner warm regions. The D${}_2$CO/HDCO ratio is only slightly larger than the HDCO/H${}_2$CO ratio. This is consistent with formaldehyde forming in the ice as soon as CO has frozen onto the grains, with most of the deuteration happening towards the end of the prestellar core phase. A comparison with available time-dependent chemical models indicates that the source is in the early Class 0 stage.

arXiv commentAccepted for publication in Astronomy and Astrophysics, 14 pages, 10 figures

References in corpus (31)

• Astropy: A Community Python Package for Astronomy
• Probing the evolutionary status of starless cores through N2H+ and N2D+ observations
• 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
• Testing grain-surface chemistry in massive hot-core regions
• Physical structure and CO abundance of low-mass protostellar envelopes
• Detection of the simplest sugar, glycolaldehyde, in a solar-type protostar with ALMA
• Near-arcsecond resolution observations of the hot corino of the solar type protostar IRAS 16293-2422
• Gas phase formation of the prebiotic molecule formamide: insights from new quantum computations
• Testing grain surface chemistry : a survey of deuterated formaldehyde and methanol in low-mass Class 0 protostars
• A study of deuterated water in the low-mass protostar IRAS16293-2422
• An interferometric study of the low-mass protostar IRAS 16293-2422: small scale organic chemistry
• Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores
• The ALMA-PILS survey: First detections of deuterated formamide and deuterated isocyanic acid in the interstellar medium
• Organic Molecules in Low-Mass Protostellar Hot Cores: Submillimeter Imaging of IRAS 16293-2422
• The ALMA-PILS survey: First detections of ethylene oxide, acetone and propanal toward the low-mass protostar IRAS 16293-2422
• New quantum chemical computations of formamide deuteration support a gas-phase formation of this prebiotic molecule
• The ALMA-PILS survey: Detection of CH${}_3$NCO toward the low-mass protostar IRAS 16293-2422 and laboratory constraints on its formation
• Arcsecond resolution images of the chemical structure of the low-mass protostar IRAS 16293-2422
• Simultaneous Hydrogenation and UV-photolysis Experiments of NO in CO-rich Interstellar Ice Analogues; linking HNCO, OCN-, NH2CHO and NH2OH
• Formaldehyde and methanol deuteration in protostars: fossiles from a past fast high density pre-collapse phase
• Galactic interstellar 18O/17O ratios - a radial gradient?
• The solar type protostar IRAS16293-2422: new constraints on the physical structure
• 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
• On the origin of H2CO abundance enhancements in low-mass protostars
• Warm water deuterium fractionation in IRAS 16293-2422 - The high-resolution ALMA and SMA view
• Detection of methylisocyanate (CH3NCO) in a solar-type protostar
• Chemistry of massive young stellar objects with a disk-like structure
• High D${}_2$O/HDO ratio in the inner regions of the low-mass protostar NGC1333 IRAS2A
• Submillimeter spectroscopy of H${}_2$C${}^{17}$O and a revisit of the rotational spectra of H${}_2$C${}^{18}$O and H${}_2$C${}^{16}$O

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