Interstellar dust within the life cycle of the interstellar medium

Demyk, K.

doi:10.1051/epjconf/20111803001

Cited by 7 publications

(3 citation statements)

References 80 publications

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“…Aggregated grains of refractory materials that have accumulated ices are components of the dust observed in prestellar cores, as well as in protostellar and protoplanetary disks (e.g., Boogert et al 2015). The refractory materials are mainly silicates and carbonaceous matter, while the ices consist essentially of water (H 2 O; e.g., Demyk 2011). The sublimation of the volatile icy content of the dust and the associated outgassing cause, for example, ice lines and spatial variations of the gas-to-dust mass ratio (e.g., Stammler et al 2017;Schoonenberg & Ormel 2017;Spadaccia et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Water transport through mesoporous amorphous-carbon dust

Basalgète,

Rouillé,

Jäger

2024

A&A

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The diffusion of water molecules through mesoporous dust of amorphous carbon (a-C) is a key process in the evolution of prestellar, protostellar, and protoplanetary dust, as well as in that of comets. It also plays a role in the formation of planets. Given the absence of data on this process, we experimentally studied the isothermal diffusion of water molecules desorbing from water ice buried at the bottom of a mesoporous layer of aggregated a-C nanoparticles, a material analogous to protostellar and cometary dust. We used infrared spectroscopy to monitor diffusion in low temperature (160 to 170 K) and pressure (6 times 10$^ $ to 8 times 10$^ $ Pa) conditions. Fick's first law of diffusion allowed us to derive diffusivity values on the order of 10$^ $ cm$^2$ s$^ $, which we linked to Knudsen diffusion. Water vapor molecular fluxes ranged from 5 times 1012 to 3 times 1014 cm$^ $ s$^ $ for thicknesses of the ice-free porous layer ranging from 60 to 1900 nm. Assimilating the layers of nanoparticles to assemblies of spheres, we attributed to this cosmic dust analog of porosity 0.80--0.90 a geometry correction factor, similar to the tortuosity factor of tubular pore systems, between 0.94 and 2.85. Applying the method to ices and refractory particles of other compositions will provides us with other useful data.

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Section: Introductionmentioning

confidence: 99%

Water transport through mesoporous amorphous-carbon dust

Basalgète,

Rouillé,

Jäger

2024

A&A

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“…Organic compounds exist in several regions of the Universe from molecular clouds of the interstellar medium (Pendleton 1997;Charnley et al 2002) till small bodies of astronomical interest such as meteorites (Yang & Epstein 1983;Llorca 2004) and comets (Fomenkova et al 1994;Biver et al 2014). It is well established that many organic molecules originate from reactions occurring on the surface of interstellar dust grains which are mainly composed of silicate, amorphous carbon and organic species (Tielens and Allamandola 1987;Draine 2003;Demyk 2011). By focusing on the formation and evolution of organic molecules on the interstellar dust grains, theoretical and experimental studies (Kimura and Kitadai 2015;Enrique-Romero et al 2016;Redondo et.…”

Section: Introductionmentioning

confidence: 99%

Organic residues in astrophysical ice analogues: Thermal processing of hydrogenated glyoxal ices under interstellar conditions

Leroux

Guillemin

Krim

2021

Monthly Notices of the Royal Astronomical Society

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Organic residues are considered as part of the chemical composition of the interstellar dust grains. They are formed under the extreme conditions of the interstellar medium and play an important role in exobiology. They may contain prebiotic organic species such as amino acids, constituents of proteins and building blocks of DNA and RNA, key elements of life. By investigating the formation of organic residues in an astrophysical context, many groups have been focusing in the UV irradiation and subsequent warm-up of astrophysical ice analogs. This aims to suggest that organic residues are mainly formed in regions of molecular clouds exposed to UV light or cosmic rays. The present study shows an organic residues formation involving glyoxal ice and H-atoms. While the hydrogenation of glyoxal at 10 K leads mainly to small molecules such as CO and H2CO and CH3OH, we show that the heating of the hydrogenated ice in the 10–300 K temperature range leads to solid residues which structure is similar to that of glycolaldehyde but they remain stable in solid phase at 300 K and atmospheric pressure. The analysis of the IR data shows that the organic residues formed through the thermal processing of CHOCHO + H reaction would be a mixture of hydroxypyruvaldehyde and methyl glyoxylate, two solid organics which formation starts with an H-abstraction from glyoxal to form CHOCO• radical which recombines to •CH2OH and •OCH3 radicals. These latter may be formed and trapped in glyoxal ice as secondary products from H2CO + H secondary reaction.

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“…The chemical study of the interstellar medium is an essential part of astrophysics 3 . This rich environment, composed of gas and dust, where very particular physical conditions reign, plays a fundamental role in the formation of new stars and the evolution of life.…”

Section: Introductionmentioning

confidence: 99%

The formation of interstellar organic molecules: H2C3O A DFT and ELF theoretical study

et al. 2019

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This quantum study at B3LYP/6-311 ++ G (d, p) with ELF analysis were performed in order to understand the formation of propynal and cyclopropenone, two molecules detected in the interstellar medium. The formation of these molecules is supposed to be through reactions between carbon monoxide (CO) and acetylene (C2H2) in the cold conditions of interstellar clouds. All the structures, reagents, products and transition states, have been optimized and the geometrical parameters are given as well as the dipole moments. The reaction paths are elaborated and discussed here using the IRC method implemented in the Gaussian program. The determined activation energies allow an estimation of the rate constants. The ELF analysis performed here seems to be a valuable tool for screening the evolution of the bonds during the formation processes. The two reactions probably occur in one step. The propadienone, another possible isomer, has been also studied. It is formed through a third reaction. A stable triplet ground state of this molecule, the thermodynamic consideration and a small dipole moment can explain the fact that it is not detected yet in the interstellar medium. M06-2X and WB97XD functional were also used for comparing results.

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Interstellar dust within the life cycle of the interstellar medium

Cited by 7 publications

References 80 publications

Water transport through mesoporous amorphous-carbon dust

Water transport through mesoporous amorphous-carbon dust

Organic residues in astrophysical ice analogues: Thermal processing of hydrogenated glyoxal ices under interstellar conditions

The formation of interstellar organic molecules: H2C3O A DFT and ELF theoretical study

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