Experimental and theoretical studies of photoinduced reactions in the solid phase of the interstellar medium

Murga, M. S.; Wiebe, D. S.; Vasyunin, A. I.; Varakin, V. N.; Stolyarov, A. V.

doi:10.1070/rcr4912

Cited by 11 publications

(6 citation statements)

References 191 publications

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“…When ultraviolet radiation sources emerge inside molecular clouds at later protostellar evolution stages, COMs are recognized to be formed during the gradual heating of a gasdust mixture (the warm-up scenario, [283]). Here, photoinduced processes in icy mantles of cosmic dust grains become essential [284]. Photons destruct the initial cold synthesis products present in the mantles after the cold protostellar phases.…”

Section: Evolution Of Organic Substancesmentioning

confidence: 99%

Objectives of the Millimetron Space Observatory science program and technical capabilities of its realization

Новиков¹,

Лихачев

Shchekinov

et al. 2021

Phys.-Usp.

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We present the scientific program of the Spectr-M project aimed at the creation and operation of the Millimetron Space Observatory (MSO) planned for launch in the late 2020s. The unique technical capabilities of the observatory will enable broadband observations of astronomical objects from 50 μm to 10 mm wavelengths with a record sensitivity (up to ∼ 0.1 μJy) in the single-dish mode and with an unprecedented high angular resolution (∼ 0.1 μas) in the ground-space very long baseline interferometer (SVLBI) regime. The program addresses fundamental priority issues of astrophysics and physics in general that can be solved only with the MSO capabilities: 1) the study of physical processes in the early Universe up to redshifts z ∼ 2 × 106 through measuring μ-distortions of the cosmic microwave background (CMB) spectrum, and investigation of the structure and evolution of the Universe at redshifts z < 15 by measuring y-distortions of the CMB spectrum; 2) the investigation of the geometry of space-time around supermassive black holes (SMBHs) in the center of our Galaxy and M87 by imaging surrounding shadows, the study of plasma properties in the shadow formation regions, and the search for observational manifestations of wormholes; 3) the study of observational manifestations of the origin of life in the Universe — the search for water and biomarkers in the Galactic interstellar medium. Moreover, the technical capabilities of the MSO can help solve related problems, including the birth of the first galaxies and SMBHs (z ≳ 10), alternative approaches to measuring the Hubble constant, the physics of SMBHs in ‘dusty’ galactic nuclei, the study of protoplanetary disks and water transport in them, and the study of ‘ocean worlds’ in the Solar System.

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Section: Evolution Of Organic Substancesmentioning

confidence: 99%

Objectives of the Millimetron Space Observatory science program and technical capabilities of its realization

Новиков¹,

Лихачев

Shchekinov

et al. 2021

Phys.-Usp.

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“…We assume that the photodesorption yield is equal to one of water Y = 3.5 × 10 −3 + 0.13 exp (−336/T mp ) (Westley et al 1995, note the misprint in the Y 0 value, caption to their Fig. 3, see also Walmsley et al (1999)), which is probably the upper boundary for experimentally measured values (Murga et al 2020).…”

Section: Photodesorptionmentioning

confidence: 99%

Section: Evolution Of Volatiles In the Gas And In The Icesmentioning

confidence: 99%

“…A CO molecule inside this line is likely to survive the photodissociation. Photodissociation could affect ice-phase species as well, but the corresponding reaction rates should probably be lower than those in the gas phase(Murga et al 2020). The details of this process are still unclear, so we chose to ignore it in our model.The short-term spikes in the position of thermal snowlines (most visible in CO 2 ) are induced by protostellar accretion bursts, which occur in gravitationally unstable disks at the early stages of their evolution (see, e.g.,Vorobyov & Basu 2015).…”

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confidence: 99%

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Gravitoviscous protoplanetary disks with a dust component. V. The dynamic model for freeze-out and sublimation of volatiles

Molyarova,

Vorobyov,

Akimkin

et al. 2021

Preprint

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The snowlines of various volatile species in protoplanetary disks are associated with abrupt changes in gas composition and dust physical properties. Volatiles may affect dust growth, as they cover grains with icy mantles that can change the fragmentation velocity of the grains. In turn, dust coagulation, fragmentation, and drift through the gas disk can contribute to the redistribution of volatiles between the ice and gas phases. Here we present the hydrodynamic model FEOSAD for protoplanetary disks with two dust populations and volatile dynamics. We compute the spatial distributions of major volatile molecules (H 2 O, CO 2 , CH 4 , and CO) in the gas, on small and grown dust, and analyze the composition of icy mantles over the initial 0.5 Myr of disk evolution. We show that most of ice arrives to the grown dust through coagulation with small grains. Spiral structures and dust rings forming in the disk, as well as photodissociation in the outer regions, lead to the formation of complex snowline shapes and multiple snowlines for each volatile species. During the considered disk evolution, the snowlines shift closer to the star, with their final position being a factor 4-5 smaller than that at the disk formation epoch. We demonstrate that volatiles tend to collect in the vicinity of their snowlines, both in the ice and gas phases, leading to the formation of thick icy mantles potentially important for dust dynamics. The dust size is affected by a lower fragmentation velocity of bare grains in the model with a higher turbulent viscosity.

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“…Complex organic molecules (COMs, molecules containing more than 6 atoms, including C and H) are species of special interest, because they are actively involved in prebiotic chemistry and are associated with the origin of life (Herbst & van Dishoeck (2009)). Methanol (CH 3 OH) is important molecule for the formation of more complex organic compounds according to a number of laboratory and theoretical studies ( Öberg et al (2009); Murga et al (2020); Rivilla et al (2019); Kochina et al (2013)). It is assumed now (see e. g. Watanabe & Kouchi (2002); Fuchs et al (2009); Linnartz et al (2015)) that methanol in ISM forms on the surface of dust particles by hydrogenation of a carbon monoxide (CO) molecule, and then desorbs into the gas phase via thermal and non-thermal processes.…”

Section: Introductionmentioning

confidence: 99%

Methanol formation chemistry with revised reactions scheme

Sokolova

2020

Preprint

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The aim of the presented work is to analyze the impact of experimentally evaluated reactions of hydrogen abstraction on surfaces of interstellar grains on the chemical evolution of methanol and its precursors on grains and in the gas phase under conditions of cold dark cloud and during the collapse of the translucent cloud into the dark cloud. Analysis of simulation results shows that those reactions are highly efficient destruction channels for HCO and H 2 CO on grain surfaces, and significantly impact the abundances of almost all molecules participating in the formation of CH 3 OH. Next, in models with those reactions maximum abundances of methanol in gas and on grain surface decrease by more than 2-3 orders of magnitude in comparison to models without surface abstraction reactions of hydrogen. Finally, we study the impact of binding energies of CH 2 OH and CH 3 O radicals on methanol chemistry.

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Experimental and theoretical studies of photoinduced reactions in the solid phase of the interstellar medium

Cited by 11 publications

References 191 publications

Objectives of the Millimetron Space Observatory science program and technical capabilities of its realization

Objectives of the Millimetron Space Observatory science program and technical capabilities of its realization

Gravitoviscous protoplanetary disks with a dust component. V. The dynamic model for freeze-out and sublimation of volatiles

Methanol formation chemistry with revised reactions scheme

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