Restructuring and destruction of hydrocarbon dust in the interstellar medium

Murga, M. S.; Khoperskov, Sergey; Wiebe, D. S.

doi:10.1134/s1063772916020104

Cited by 13 publications

(19 citation statements)

References 120 publications

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“…We have modelled the evolution of PAHs at the conditions of the Orion Bar using our dust evolution model described in the work of Murga et al (2016). We have obtained the results which are generally consistent with observations but with some exceptions.…”

supporting

confidence: 67%

Orion Bar as a window to evolution of small carbonaceous dust grains

2018

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supporting

confidence: 67%

Orion Bar as a window to evolution of small carbonaceous dust grains

2018

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“…According to [14], the rate of production of acetylene R PAH for such a molecule with U = 2 × 10 4 MMP83 can be roughly estimated as 10 −7 molecules s −1 . That is, such a molecule will be completely destructed in one year.…”

Section: Ismmentioning

confidence: 99%

“…Therefore, it is more correct to compare the rates of formation of acetylene taking into account the numbers of grains with various sizes. Let us consider the grain size distribution, dn/da, from [34], supposing that all grains with radii smaller than 10Å are PAHs that can be destroyed in accordance with the model of [14], and that all the remaining grains are coated in mantles of benzene molecules. The rate of production of acetylene molecules from [14] for PAHs with various sizes is proportional to U.…”

Section: Ismmentioning

confidence: 99%

“…In modern models for the evolution of dust [14,33], the photodestruction of large grains is treated not in the context of vaporization of the grain mantles, but instead only for grains of hydrogenated amorphous carbon (HAC), from whose surfaces only hydrogen atoms are emitted, so that the grain material gradually becomes poorer in hydrogen. Figure 3 shows the ratio of the number of desorbed hydrogen atoms in the HAC model described in [14] to the number estimated from the results of our current study. It is obvious that hydrogen atoms can be emitted from the surface of HAC much more efficiently than from a benzene mantle.…”

Section: Ismmentioning

confidence: 99%

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The Photolysis of Aromatic Hydrocarbons Adsorbed on the Surfaces of Cosmic Dust Grains

et al. 2019

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The work is devoted to the adaptation of the results of laboratory studies of the laser-induced dissociation of molecules of benzene adsorbed on a quartz substrate to the conditions of the interstellar medium. Adsorption was performed under conditions of low temperature and deep vacuum. The difference between the photolysis of adsorbed molecules and molecules in the gas phase is identified.Significance of process of photolytic desorption in the interstellar conditions is analyzed, in particular, in the conditions of photodissociation regions. It is shown that the efficiency and dissociation channels of photolysis of adsorbed and gas phase benzene differ substantially. It is concluded that the photolysis of aromatic hydrocarbons adsorbed on the interstellar dust grains contributes a negligible fraction to the abundance of small hydrocarbons in the interstellar medium.

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“…In [16] (further Paper I), we presented a model for the evolution of an ensemble of hydrocarbon grains that includes aromatization of hydrocarbon particles, along with the more standard processes of destruction by UV radiation and energetic gas particles and shattering in grain-grain collisions. We continue this work in our current study, and present examples of our modeling of the evolution of an ensemble of dust grains in the ISM and corresponding variations in their emission spectra.…”

Section: Introductionmentioning

confidence: 99%

The evolution of hydrocarbon dust grains in the interstellar medium and its influence on the infrared spectra of dust

2016

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We present evolutionary calculations for the size and aromatization degree distributions of interstellar dust grains, driven by their destruction by radiation, collisions with gas particles, and shattering due to grain-grain collisions. Based on these calculations we model dust emission spectra. The initial grain size distribution play the important role in the evolution of an ensemble of dust particles. Radiation in the considered intensity range mostly aromatizes grains. The smallest grains are mainly destructed via sputtering by collisions with gas particles. There are no grains smaller than 20Å in the medium at relative gas-dust velocities more than 50 km/s, which is typical for shocks in supernova remnants. The IR emission spectrum changes significantly due to the dust evolution depending on the adopted grain properties, in particular, on the energy of the C-C bonds (E 0 ). Aromatic bands in the near-IR (2-15 µm) are absent, if E 0 is low, even when the medium properties correspond to the average interstellar medium in our Galaxy. As in reality these bands are observed, high E 0 values are more preferable. We consider dependence of the emission intensity ratios for various photometric bands on the medium properties. The aromatization degree of small grains shows up most strongly in the I 3.4 /I 11.3 intensity ratio while the fraction of aromatic grains in the total dust mass influences the I 3.3 /I 70+160 ratio.

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Restructuring and destruction of hydrocarbon dust in the interstellar medium

Cited by 13 publications

References 120 publications

Orion Bar as a window to evolution of small carbonaceous dust grains

Orion Bar as a window to evolution of small carbonaceous dust grains

The Photolysis of Aromatic Hydrocarbons Adsorbed on the Surfaces of Cosmic Dust Grains

The evolution of hydrocarbon dust grains in the interstellar medium and its influence on the infrared spectra of dust

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