Comet Halley as an aggregate of interstellar dust and further evidence for the photochemical formation of organics in the interstellar medium

Briggs, Robert G.; Ertem, Gözen; Ferris, James P.; Greenberg, J. Mayo; McCain, P. J.; Mendoza-Gomez, C. X.; Schütte, W. A.

doi:10.1007/bf01810858

Cited by 197 publications

(118 citation statements)

References 51 publications

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“…The solid layer that developed on the solid surface was analyzed by enantioselective gas chromatography and mass spectrometry GC-MS. After the analytical steps of extraction, hydrolysis, and derivatization, 16 amino acids, including 6 protein amino acids, were identified in the simulated ice mantle of interstellar dust particles (Muñoz Caro et al 2002). These amino acid identifications confirmed the preliminary amino acid formation obtained by Mayo Greenberg (Briggs et al 1992). The chiral amino acids were racemic.…”

Section: Definitionsupporting

confidence: 83%

E

2015

Encyclopedia of Astrobiology

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DefinitionThe Earth is the planet on which we live. It is the third planet from the Sun and one of the telluric (small and rocky) planets of our ▶ Solar System. It has a mean radius of 6,371 km and a mean density of 5.515 g cm À3 . It is distinguished from other planets by the presence of ▶ continental crust, oceans, and ▶ life. Its unusually large core and satellite (the Moon) are believed to result from the collision of a Mars-sized body (protoplanet ▶ Theia) about 4.45 Ga ago.

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Section: Definitionsupporting

confidence: 83%

E

2015

Encyclopedia of Astrobiology

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“…The strongest peak in this region, at 1586 cm −1 , is most probably due to the -COO − antisymmetric stretch of carboxylic acid salts [(R-COO − )(NH + 4 )]. In order to test this assumption, glycolic acid (HOCH 2 COOH; Aldrich 99%), the most abundant carboxylic acid found in residues (Agarwal et al 1985;Briggs et al 1992) and ammonia, NH 3 , were deposited simultaneously at 12 K. A reaction takes place already at 12 K, leading to the formation of a sharp peak at 1586 cm −1 Table 1. Parameters of the experiments.…”

Section: The Standard Experimentsmentioning

confidence: 99%

“…This material is generally called refractory organic residue or simply residue. Large organic compounds are produced either by ice photoprocessing (Agarwal et al 1985;Briggs et al 1992;Bernstein et al 1995Bernstein et al , 2002Muñoz Caro et al 2002 or by ion bombardment (e.g. Strazzulla & Baratta 1992;Kobayashi et al 1995;Kaiser & Roessler 1998;Cottin et al 2001).…”

Section: Introductionmentioning

confidence: 99%

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

Muñoz

Schütte

2003

A&A

162

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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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“…Excellent, detailed descriptions of the UV induced chemical evolution of interstellar ice analogs can be found in the literature. [130,134,145,[211][212][213][214] The role of methanol in the ice photochemistry discussed here is very critical to the kinds of compounds produced.…”

Section: Photochemical Evolution Of the Organic Materials In Interstelmentioning

confidence: 99%

“…Also, many alkaloids have aromatic base skeletons. In addition, other interstellar ice simulation experiments are known to produce amino acids [214,240], as well as glycerol the precursors of simple sugars. Thus, comets might represent quite potent prebiotic cocktails.…”

Section: Interstellar Pahs Ices and The Origin Of Lifementioning

confidence: 99%

From Interstellar Polycyclic Aromatic Hydrocarbons and Ice to Astrobiology

Allamandola

Hudgins

2003

Solid State Astrochemistry

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Tremendous strides have been made in our understanding of interstellar material over the past twenty years thanks to significant, parallel developments in observational astronomy and laboratory astrophysics. Twenty years ago the composition of interstellar dust was largely guessed at, the concept of ices in dense molecular clouds ignored, and the notion of large, abundant, gas phase, carbon rich molecules widespread throughout the interstellar medium (ISM) considered impossible.Today the composition of dust in the diffuse ISM is reasonably well constrained to micron-sized cold refractory materials comprised of amorphous and crystalline silicates mixed with an amorphous carbonaceous material containing aromatic structural units and short, branched aliphatic chains. In dense molecular clouds, the birthplace of stars and planets, these cold dust particles are coated with mixed molecular ices whose major components are is very well constrained. Lastly, the signature of carbon-rich polycyclic aromatic hydrocarbons (PAHs), shockingly large molecules by earlier interstellar chemistry standards, is widespread throughout the Universe. This paper presents a detailed summary of these disparate interstellar components and ends by considering both of them as important feedstock to the chemical inventory of the primordial Earth. Particular attention is paid to their possible role in the chemistry that led to the origin of life. An extensive reference list is given to allow the student entry into the full depth of the literature.The first part of this paper focuses on interstellar PAHs. The laboratory and theoretical underpinning which supports the PAH model is reviewed in some detail. This is followed by a few specific examples which demonstrate how these data can be used to analyze the interstellar spectra and probe local conditions in different emission zones. These examples include tracing the evolution of carbon as it passes from its birthsite in circumstellar shells through the ISM, determining specifics about the cosmic PAH population in many different environments including PAH size and structure, and probing local conditions in the different emission zones.The second part of this paper summarizes the laboratory and observational background leading to our current understanding of interstellar/precometary ices. Although the most abundant interstellar ice components are the very simple molecules such as H 2 O, CH 3 OH, CO, CO 2 , and NH 3 , more complex species including accreted PAHs and those formed by UV and cosmic ray processing within the ice must also be present. Here we give a detailed summary of the photochemical evolution on those ices 2 found in the densest regions of molecular clouds, the regions where stars and planetary systems are formed. Ultraviolet photolysis of these ices produces a host of new compounds, some of which show intriguing prebiotic behavior.The last part of this paper draws all this information together and considers the possible roles these compounds might have played in early Earth...

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Comet Halley as an aggregate of interstellar dust and further evidence for the photochemical formation of organics in the interstellar medium

Cited by 197 publications

References 51 publications

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

From Interstellar Polycyclic Aromatic Hydrocarbons and Ice to Astrobiology

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