J/A+A/668/A46ivo://CDS.VizieR/J/A+A/668/A46doi:10.26093/cds/vizier.36680046CDSMueller B.Giuliano B.M.Vasyunin A.Fedoseev G.Caselli P.2024-11-28T20:01:29Z2022-12-01T08:25:44ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frinfrared-astronomyspectroscopyThe pre-stellar core L1544 has been the subject of several observations conducted in the past years, complemented by modelling studies focused on its gas and ice-grain chemistry. The chemical composition of the ice mantles reflects the environmental physical changes along the temporal evolution, such as density and temperature. The investigation outcome hints at a layered structure of interstellar ices with abundance of H_2_O in the inner layers and an increasing concentration of CO near the surface. The morphology of interstellar ice analogues can be investigated experimentally assuming a composition derived from chemical models. This research presents a new approach of a three-dimensional fit where observational results are first fitted with a gas-grain chemical model predicting the exact ice composition including infrared (IR) inactive species. Then the laboratory IR spectra are recorded for interstellar ice analogues whose compositions reflect the obtained numerical results, in a layered and in a mixed morphology. These results could then be compared with the results of James Webb Space Telescope (JWST) observations. Special attention is paid to the inclusion of IR inactive species whose presence is predicted in the ice, but is typically omitted in the laboratory obtained data. This stands for N_2_, one of the main possible constituents of interstellar ice mantles, and O_2_. Ice analogue spectra were recorded at a temperature of 10K using a Fourier transform infrared spectrometer. In the case of layered ice we deposited a H_2_O-CO-N_2_-O_2_ mixture on top of a H_2_O-CH_3_OH-N_2_ ice, while in the case of mixed ice we examined a H_2_O-CH_3_OH-N_2_-CO composition. The selected species are the four most abundant ice components predicted by the chemical model. Results. Following the changing composition and structure of the ice, we find differences in the absorption bands for most of the examined vibrational modes. The extent of observed changes in the IR band profiles will allow us to analyse the structure of ice mantles in L1544 from future observations by the JWST. Our spectroscopic measurements of interstellar ice analogues predicted by our well-received gas-grain chemical codes of pre-stellar cores will allow detailed comparison with upcoming JWST observations. This is crucial in order to put stringent constraints on the chemical and physical structure of dust icy mantles just before the formation of stars and protoplanetary disks, and to explain surface chemistry.2022A&A...668A..46Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/668/A46CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/620/A46 : O2 signature in thin and thick O2-H2O ices (Mueller+, 2018)J/A+A/629/A112 : Complex refractive index of CO ice (Giuliano+, 2019)J/A+A/652/A126 : Spectroscopy of CH3OH in layered & mixed ices (Mueller+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/668/A46https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/668/A46http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/668/A46https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/668/A46https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/668/A46http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/668/A46GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfrareddefaultJ/A+A/668/A46/elayer1Layer 1, H2O:CH3OH:N2 = 100%:67.5%:27.5%recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWavenumberWavenumbercm**-1em.wavenumberdoubleAbsorbanceAbsorbancephys.absorptiondoubleJ/A+A/668/A46/elayer2Layer 2, H2O:N2:CO:O2 = 100%:46%:146%:38%AbsorbanceAbsorbancephys.absorptiondoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWavenumberWavenumbercm**-1em.wavenumberdoubleJ/A+A/668/A46/elayer21Layer 2 on top of Layer 1recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWavenumberWavenumbercm**-1em.wavenumberdoubleAbsorbanceAbsorbancephys.absorptiondoubleJ/A+A/668/A46/emixedMixed, H2O:CH3OH:N2:CO = 100%:58%:29%:37recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWavenumberWavenumbercm**-1em.wavenumberdoubleAbsorbanceAbsorbancephys.absorptiondoubleJ/A+A/668/A46/mlaymfrPredicted molecular fractional abundances for each layerrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintML[0/161] Number of the monolayermeta.idintbH2OH_2_O fraction of a monolayerphys.atmoldoublebCH4OCH_3_OH fraction of a monolayerphys.atmoldoublebCOCO fraction of a monolayerphys.atmoldoublebN2N_2_ fraction of a monolayerphys.atmoldoublebH2COH_2_CO fraction of a monolayerphys.atmoldoublebNH3NH_3_ fraction of a monolayerphys.atmoldoublebH2H_2_ fraction of a monolayerphys.atmoldoublebH2O2H_2_O_2_ fraction of a monolayerphys.atmoldoublebO2O_2_ fraction of a monolayerphys.atmoldouble