Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores

Abstract

Extremely large deuteration of several molecules has been observed towards prestellar cores and low-mass protostars for a decade. New observations performed towards low-mass protostars suggest that water presents a lower deuteration in the warm inner gas than in the cold external envelope. We coupled a gas-grain astrochemical model with a one-dimension model of collapsing core to properly follow the formation and the deuteration of interstellar ices as well as their subsequent evaporation in the low-mass protostellar envelopes with the aim of interpreting the spatial and temporal evolutions of their deuteration. The astrochemical model follows the formation and the evaporation of ices with a multilayer approach and also includes a state-of-the-art deuterated chemical network by taking the spin states of H${}_2$ and light ions into account. Because of their slow formation, interstellar ices are chemically heterogeneous and show an increase of their deuterium fractionation towards the surface. The differentiation of the deuteration in ices induces an evolution of the deuteration within protostellar envelopes. The warm inner region is poorly deuterated because it includes the whole molecular content of ices while the deuteration predicted in the cold external envelope scales with the highly deuterated surface of ices. We are able to reproduce the observed evolution of water deuteration within protostellar envelopes but we are still unable to predict the super-high deuteration observed for formaldehyde and methanol. Finally, the extension of this study to the deuteration of complex organics (COMs), important for the prebiotic chemistry, shows a good agreement with the observations, suggesting that we can use the deuteration to retrace their mechanisms and their moments of formation.

22 pages, 11 figures. Accepted for publication in The Astrophysical Journal

References in corpus (12)

• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• Non-thermal desorption from interstellar dust grains via exothermic surface reactions
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• Observing the gas temperature drop in the high-density nucleus of L 1544
• Polycylcic Aromatic Hydrocarbons (PAH's) in dense cloud chemistry
• Simulation of the Formation and Morphology of Ice Mantles on Interstellar Grains
• First detection of triply-deuterated methanol
• Photodesorption of water ice: a molecular dynamics study
• The importance of the ortho:para H2 ratio for the deuteration of molecules during pre-protostellar collapse
• Molecular oxygen in the rho Ophiuchi cloud
• Desorption of CO and O2 interstellar ice analogs
• Warm water deuterium fractionation in IRAS 16293-2422 - The high-resolution ALMA and SMA view

Cited by in corpus (65)

• 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
• Formation of complex organic molecules in cold objects: the role of gas phase reactions
• Astrochemistry During the Formation of Stars
• Constraining the abundances of complex organics in the inner regions of solar-type protostars
• Formation of complex organic molecules in hot molecular cores through nondiffusive grain-surface and ice-mantle chemistry
• Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
• Formation of Complex Organic Molecules in Cold Interstellar Environments through non-diffusive grain-surface and ice-mantle chemistry
• CORINOS I: JWST/MIRI Spectroscopy and Imaging of a Class 0 protostar IRAS 15398-3359
• Complex organic molecules in low-mass protostars on solar system scales -- I. Oxygen-bearing species
• Benchmarking spin-state chemistry in starless core models
• A primordial origin for molecular oxygen in comets: A chemical kinetics study of the formation and survival of O${}_2$ ice from clouds to disks
• Complex organic molecules in low-mass protostars on Solar System scales -- II. Nitrogen-bearing species
• Water delivery from cores to disks: deuteration as a probe of the prestellar inheritance of H2O
• Why does ammonia not freeze out in the center of pre-stellar cores?
• The composition of the protosolar disk and the formation conditions for comets
• Decrease of the organic deuteration during the evolution of Sun-like protostars: the case of SVS13-A
• Prestellar grain-surface origins of deuterated methanol in comet 67P/Churyumov-Gerasimenko
• Chemical Variation among Protostellar Cores: Dependence on Prestellar Core Conditions
• High D${}_2$O/HDO ratio in the inner regions of the low-mass protostar NGC1333 IRAS2A
• The detection of a hot molecular core in the extreme outer Galaxy
• Chemical Segregation in Hot Cores With Disk Candidates: An investigation with ALMA
• Seeds of Life in Space (SOLIS). VI. Chemical evolution of sulfuretted species along the outflows driven by the low-mass protostellar binary NGC1333-IRAS4A
• ALMA observations of water deuteration: A physical diagnostic of the formation of protostars
• Deuterated methanol on Solar System scale around the HH212 protostar
• Water deuterium fractionation in the high-mass star-forming region G34.26+0.15 based on Herschel/HIFI data
• JWST observations of ${}^{13}$CO${}_2$ ice: Tracing the chemical environment and thermal history of ices in protostellar envelopes
• X-ray induced chemistry of water and related molecules in low-mass protostellar envelopes
• A novel framework to study the impact of binding energy distributions on the chemistry of dust grains
• A Survey of CH2DOH Towards Starless and Prestellar Cores in the Taurus Molecular Cloud
• Organic chemistry in the protosolar analogue HOPS-108: Environment matters
• Chemical survey of Class I protostars with the IRAM-30m
• Successive deuteration in low-mass star-forming regions: the case of D${}_2$-methanol (CHD${}_2$OH) in IRAS 16293-2422
• JWST detections of amorphous and crystalline HDO ice toward massive protostars
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): I. Detection of New Hot Corinos with ACA
• Methanol deuteration in high-mass protostars
• Sulphur-rich cold gas around the hot core precursor G328.2551-0.5321. An APEX unbiased spectral survey of the 2 mm, 1.2 mm, and 0.8 mm atmospheric windows
• Quantifying the chemical desorption of H${}_2$S and PH${}_3$ from amorphous water ice surfaces
• A cryogenic ice setup to simulate carbon atom reactions in interstellar ices
• A Revised Description of the Cosmic Ray-Induced Desorption of Interstellar Ices
• H2CS deuteration maps towards the pre-stellar core L1544
• Rotational spectroscopy of mono-deuterated oxirane ($c$-C${}_2$H${}_3$DO) and its detection towards IRAS 16293$-$2422 B
• The connection between warm carbon chain chemistry and interstellar irradiation of star-forming cores
• A 3D physico-chemical model of a pre-stellar core. I. Environmental and structural impact on the distribution of CH${}_3$OH and $c$-C${}_3$H${}_2$
• Rotational and rovibrational spectroscopy of CD${}_3$OH with an account of CD${}_3$OH toward IRAS 16293$-$2422
• Enhanced formation of interstellar complex organic molecules on carbon monoxide ice
• ALMA Observations of the IRDC Clump G34.43+00.24 MM3: DNC/HNC Ratio
• A D/H Ratio Consistent with Earth's Water in Halley-type Comet 12P from ALMA HDO Mapping
• First detection of CHD${}_2$OH towards pre-stellar cores
• Millimetre and sub-millimetre spectroscopy of doubly deuterated acetaldehyde (CHD2CHO) and first detection towards IRAS 16293-2422
• Deuterium chemistry and D/H ratios in Class 0/I proto-brown dwarfs
• Rotational spectroscopy of oxirane-\textit{2,2}-$d_2$, $c$-CD${}_2$CH${}_2$O, and its tentative detection toward IRAS 16293$-$2422~B
• A multigrain-multilayer astrochemical model with variable desorption energy for surface species
• Investigation of the rotational spectrum of CD${}_3$OD and an astronomical search toward IRAS 16293$-$2422
• The first interferometric measurements of NH${}_2$D/NH${}_3$ ratio in hot corinos
• Analysis of Low Excitation HDO Transitions Toward the High-Mass Star-forming Regions G34.26+0.15, W51e${}_1$/e${}_2$, and W49N
• A survey of HDCO and D${}_2$CO towards Class 0/I proto-brown dwarfs
• Dust temperature and time-dependent effects in the chemistry of photodissociation regions
• Physicochemical models: source-tailored or generic?
• Broadband infrared spectroscopy of methanol isotopologues in pure, H2O-rich, and CO-rich ice analogues
• Protostellar Interferometric Line Survey of the Cygnus-X region (PILS-Cygnus) -- The role of the external environment in setting the chemistry of protostars
• Isotopomer-Specific Carbon Isotope Ratio of Complex Organic Molecules in Star-Forming Cores
• Deuterated forms of H${}_3^{+}$ and their importance in astrochemistry
• Modeling the UV-photon irradiation of CS${}_2$-bearing ices in the laboratory with the pyRate gas-grain astrochemical code. New insights into the missing sulfur problem
• Survival of Molecular Complexity under Recent Supernova Feedback: Detection of Hot Cores in RX J1713.7-3946
• On the Formation of Deuterated Methyl Formate in Hot Corinos