4.6 micron absorption features due to solid phase CO and cyano group molecules toward compact infrared sources

Lacy, J. H.; Baas, F.; Allamandola, Louis J.; Bult, C. E. P. M. van de; Persson, S. E.; McGregor, Peter; Lonsdale, Colin J.; Geballe, T. R.

doi:10.1086/161642

Cited by 206 publications

(137 citation statements)

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“…In many cases, an absorption band results which is remarkably similar to that seen in the interstellar medium in both proÐle and peak position (Moore et al 1983 ;Lacy et al 1984 ;Grim & Greenberg 1987 ;Tegler et al 1993 ;Schutte & Greenberg 1997 ;Demyk et al 1998 ;Palumbo et al 2000 ;Hudson & Moore 2000). Here we report irradiation experiments using ion bombardment of and ices.…”

Section: Introductionmentioning

confidence: 57%

“…Although the magnitude of the shift in isotopic-labeling experiments reveals something about the distances of the atoms from the central action, there are complications that can be envisaged. First attempts at identifying the structure of the 4.62 km band were made by Lacy et al 1984, who suggested that the carrier contains nitrile (wC¹N) groups. Upon further study, Bernstein, Sandford, & Allamandola (1997) presented arguments that isonitriles (wN¹C) are slightly favored over nitriles.…”

Section: Significance Of Resultsmentioning

confidence: 99%

“…First observed toward the massive protostar W33A (Soifer et al 1979), the 4.62 km band peak was later identiÐed with a C¹N functional group (Lacy et al 1984). This band has now been detected toward a number of other deeply embedded protostars (Weintraub et al 1994 ;Tegler et al 1995 ;Pendleton et al 1999) in dense molecular clouds, but it does not appear in the spectra of di †use interstellar medium (ISM) dust (Whittet et al 2000b).…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen Isotopic Substitution Studies of the 2165 Wavenumber (4.62 Micron) “XCN” Feature Produced by Ion Bombardment

Palumbo

Pendleton

Strazzulla

2000

ApJ

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The interstellar 4.62 km absorption band, commonly seen toward embedded protostellar objects, has not yet been unambiguously identiÐed ; here we report new results which further elucidate the components of the band carrier, which is often referred to in the literature as the "" XCN ÏÏ band due to previous implications of carbon and nitrogen. If the atmosphere of the early Earth was not overly reducing, as some studies indicate, production of prebiotic molecules containing the cyanogen bond would have been difficult. In that case, CN-bearing molecules, necessary for the origin of life, may have come primarily from extraterrestrial sources, and the interstellar medium may be an important source of those molecules. Laboratory studies show that energetic processing of ice mixtures containing H, C, N, and O atoms readily reproduce a band similar in peak position and proÐle to that seen in the interstellar spectra. Earlier isotopic labeling experiments clearly identiÐed carbon, nitrogen, and oxygen as active participants of the XCN species. In this paper, results of ion bombardment of and CH 3 OH : N 2 ices are presented. A shift in band position resulting from deuterium substitution demon-CD 3 OD : N 2 strates that hydrogen is also a component of the carrier in the laboratory-produced 4.62 km band. Irradiation of ices through ion bombardment allows the testing of mixtures which include a possible N 2 , source of the available nitrogen in dense cloud ices that cannot be probed through UV photolysis experiments.

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Section: Introductionmentioning

confidence: 57%

Section: Significance Of Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydrogen Isotopic Substitution Studies of the 2165 Wavenumber (4.62 Micron) “XCN” Feature Produced by Ion Bombardment

Palumbo

Pendleton

Strazzulla

2000

ApJ

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“…Knacke et al (1985) have reported an upper limit to the gas-phase interstellar CH 4 /CO abundance ratio of 10-2 • It is generally assumed that any missing elemental carbon is contained in interstellar grains. The detection of the appropriate infrared absorption and/or emission bands has revealed the existence of species in the condensed phase containing CH and/or CO bonds (Leger and Puget, 1984;Lacy et al, 1984;Allamandola et al, 1985). The amount of carbon appears to be less than the amount of gas-phase CO.…”

Section: Discussionmentioning

confidence: 99%

Evidence for methane and ammonia in the coma of comet P/Halley

Allen

Delitsky

Huntress

et al. 1988

Exploration of Halley’s Comet

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Summary. Methane and ammonia abundances in the coma of Halley are derived from Giotto IMS data using an Eulerian model of chemical and physical processes inside the contact surface to simulate Giotto HIS ion mass spectral data for mass-to-charge ratios (m/q) from 15 to 19. The ratio m/q = 19/18 as a function of distance from the nucleus is not reproduced by a model for a pure water coma. It is necessary to include the presence of NH 3 , and uniquely NH 3 , in coma gases in order to explain the data. A ratio of production rates Q(NH3)/Q(H20) = 0.01-Q.02 results in model values approximating the Giotto data. Methane is identified as the most probable source of the distinct peak at m/q = 15. The observations are fit best with Q(CH4 )/Q(H2 0) = 0.02. The chemical composition of the comet nucleus implied by these production rate ratios is unlike that of the outer planets. On the other hand, there are also significant differences from observations of gas phase interstellar material.

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“…The 4.62 µm absorption feature has now unambiguously been attributed to the OCN − ion (Schutte & Greenberg 1997, Demyk et al 1998. Early photolysis experiments on ices revealed that this band grows immediately upon photolysis (Lacy et al 1984). It persists even after the ice evaporates and is associated with an inorganic salt (Grim & Greenberg 1987, Schutte & Khanna 2003.…”

Section: Carbonaceous Solids In Dense Molecular Cloudsmentioning

confidence: 99%

The origin and evolution of interstellar organics

Chiar

Pendleton²

2008

Proc. IAU

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Abstract. Over the last decade, we have made great strides in better understanding dust composition and evolution in dense clouds and the diffuse interstellar medium (ISM). Thanks to improvements in IR detector sensitivity on ground-based telescopes and the Spitzer Space Telescope mission, we are no longer limited to a handful of bright background stars in order to study dust composition in quiescent dense clouds and the diffuse ISM. More thorough sampling of lines of sight in these regions has highlighted the dichotomy of the nature and composition of dust in these environments. In addition, successes in recreating interstellar processes and dustanalogs in the laboratory have helped us to understand the differences in dust absorption features we observe in the ISM. In this article, we focus on the organic components of interstellar dust, reviewing past work and highlighting the most recent observations and laboratory experiments.

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4.6 micron absorption features due to solid phase CO and cyano group molecules toward compact infrared sources

Cited by 206 publications

References 0 publications

Hydrogen Isotopic Substitution Studies of the 2165 Wavenumber (4.62 Micron) “XCN” Feature Produced by Ion Bombardment

Hydrogen Isotopic Substitution Studies of the 2165 Wavenumber (4.62 Micron) “XCN” Feature Produced by Ion Bombardment

Evidence for methane and ammonia in the coma of comet P/Halley

The origin and evolution of interstellar organics

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