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Fomenkova, M. N.

doi:10.1023/a:1005237828783

Cited by 72 publications

(33 citation statements)

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“…A large fraction of the cometary organics, about 50%, are oxygen-rich (O/C ≥ 0.4); these compounds are consistent with structures of alcohols, aldehydes, ketones, acids and amino acids, and their salts, although the exact makeup of these molecules can not be unambiguously identified (Fomenkova 1994(Fomenkova , 1999. The O/C ratio of the oxygen-rich fraction in comets is similar to the residue of the standard experiment, OR1 (Sect.…”

Section: Astrophysical Implicationssupporting

confidence: 51%

“…Cometary dust is rich in organics, as much as 50% by mass (Fomenkova 1999). A large fraction of the cometary organics, about 50%, are oxygen-rich (O/C ≥ 0.4); these compounds are consistent with structures of alcohols, aldehydes, ketones, acids and amino acids, and their salts, although the exact makeup of these molecules can not be unambiguously identified (Fomenkova 1994(Fomenkova , 1999.…”

Section: Astrophysical Implicationsmentioning

confidence: 99%

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UV-photoprocessing of interstellar ice analogs: New infrared spectroscopic results

Muñoz

Schütte

2003

A&A

163

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Abstract. We simulate experimentally the physical conditions present in dense clouds by means of a high vacuum experimental setup at low temperature T ≈ 12 K. The accretion and photoprocessing of ices on grain surfaces is simulated in the following way: an ice layer with composition analogous to that of interstellar ices is deposited on a substrate window, while being irradiated by ultraviolet (UV) photons. Subsequently the sample is slowly warmed up to room temperature; a residue remains containing the most refractory products of photo-and thermal processing. In this paper we report on the Fourier transform-infrared (FT-IR) spectroscopy of the refractory organic material formed under a wide variety of initial conditions (ice composition, UV spectrum, UV dose and sample temperature). The refractory products obtained in these experiments are identified and the corresponding efficiencies of formation are given. The first evidence for carboxylic acid salts as part of the refractory products is shown. The features in the IR spectrum of the refractory material are attributed to hexamethylenetetramine (HMT, [(CH 2 ) 6 N 4 ]), ammonium salts of carboxylic acids [(R-COO − )(NH + )], amides [H 2 NC(=O)-R], esters [R-C(=O)-O-R ] and species related to polyoxymethylene (POM, [(-CH 2 O-) n ]). Furthermore, evidence is presented for the formation of HMT at room temperature, and the important role of H 2 O ice as a catalyst for the formation of complex organic molecules. These species might also be present in the interstellar medium (ISM) and form part of comets. Ongoing and future cometary missions, such as Stardust and Rosetta, will allow a comparison with the laboratory results, providing new insight into the physico-chemical conditions present during the formation of our solar system.

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Section: Astrophysical Implicationssupporting

confidence: 51%

Section: Astrophysical Implicationsmentioning

confidence: 99%

UV-photoprocessing of interstellar ice analogs: New infrared spectroscopic results

Muñoz

Schütte

2003

A&A

163

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“…The composition of carbonaceous dust particles from comet Halley is discussed in and reviewed by Fomenkova (1997Fomenkova ( , 1999. According to these studies, the carbon found in solid materials (dust particles) is distributed over a number of phases with different compositions.…”

Section: Analysis Of Cometary Materialsmentioning

confidence: 99%

Spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals

Gail

Trieloff

2017

A&A

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Context. A high fraction of carbon bound in solid carbonaceous material is observed to exist in bodies formed in the cold outskirts of the solar nebula, while bodies in the region of terrestrial planets contain only very small mass fractions of carbon. Most of the solid carbon component is lost and converted into CO during the spiral-in of matter as the Sun accretes matter from the solar nebula. Aims. We study the fate of the carbonaceous material that entered the proto-solar disc by comparing the initial carbon abundance in primitive solar system material and the abundance of residual carbon in planetesimals and planets in the asteroid belt and the terrestrial planet region. Methods. We constructed a model for the composition of the pristine carbonaceous material from observational data on the composition of the dust component in comets and of interplanetary dust particles and from published data on pyrolysis experiments. This material entered the inner parts of the solar nebula during the course of the build-up of the proto-sun by accreting matter from the proto-stellar disc. Based on a one-zone evolution model of the solar nebula, we studied the pyrolysis of the refractory and volatile organic component and the concomitant release of hydrocarbons of high molecular weight under quiescent conditions of disc evolution, while matter migrates into the central parts of the solar nebula. We also studied the decomposition and oxidation of the carbonaceous material during violent flash heating events, which are thought to be responsible for the formation of chondrules. To do this, we calculated pyrolysis and oxidation of the carbonaceous material in temperature spikes that were modeled according to cosmochemical models for the temperature history of chondrules. Results. We find that the complex hydrocarbon components of the carbonaceous material are removed from the disc matter in the temperature range between 250 and 400 K, but the amorphous carbon component survives to temperatures of 1200 K. Without efficient carbon destruction during flash-heating associated with chondrule formation, the carbon abundance of terrestrial planets, except for Mercury, would be of several percent and not as low as it is found in cosmochemical studies. Chondrule formation seems to be a crucial process for the carbon-poor composition of the material of terrestrial planets.

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“…The most complex species identified were acetaldehyde and methyl formate. However, the presence of more complex, still unidentified species was indicated in the exploration of comet Halley, from mass spectroscopy and from evidence of an organic refractory component in cometary grains (Mitchell et al 1987;Fomenkova 1999).…”

Section: Introductionmentioning

confidence: 99%