Optical constants of cosmic carbon analogue grains — I. Simulation of clustering by a modified continuous distribution of ellipsoids

Zubko, V. G.; Mennella, V.; Colangeli, L.; Bussoletti, E.

doi:10.1093/mnras/282.4.1321

Cited by 520 publications

(561 citation statements)

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“…We note that the scattering fraction (see Fig. 19) decreases as the band gap of the material decreases but is still significant for materials with band gaps as low as 1.5 eV... Zubko et al (1996) data. Zubko et al (1996) data. in real parts of the complex refractive indices, n, are not discernable in this type of plot and these figures are therefore not reproduced here.…”

Section: Scattering By A-c(:h) Grains At Mid-ir Wavelengthsmentioning

confidence: 75%

Variations on a theme – the evolution of hydrocarbon solids (Corrigendum)

Jones

2012

A&A

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Section: Scattering By A-c(:h) Grains At Mid-ir Wavelengthsmentioning

confidence: 75%

Variations on a theme – the evolution of hydrocarbon solids (Corrigendum)

Jones

2012

A&A

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“…We base our study on the optical property data of (hydrogenated) amorphous carbons available from Smith (1984), Rouleau & Martin (1991), Mennella et al (1995), Zubko et al (1996) and the Jena group's "Databases of Dust Optical Properties" (DDOP) 1 . These data represent experimentally-derived optical properties (in some cases the data have been extended by modelling) for a range of solid (hydro)carbon materials as a function of the preparation method and/or the material annealing temperature.…”

Section: The Measured Optical Properties Of Amorphous Hydrocarbons Frmentioning

confidence: 99%

“…In this respect the carbon component of cosmic dust presents a real challenge because its behaviour in the interstellar medium (ISM) is probably far from being completely understood. There are a number of laboratory-based determinations of the optical constants for carbonaceous dust ranging over the whole gamut from graphite to (nano)diamond (e.g., Draine & Lee 1984;Lewis et al 1989;Mennella et al 1995;Rouleau & Martin 1991;Zubko et al 1996). There has also been a theoretical determination of the optical properties, in the visible-UV wavelength range, of a very wide range of amorphous carbons by Kassavetis et al (2007).…”

Section: Introductionmentioning

confidence: 99%

Variations on a theme – the evolution of hydrocarbon solids

Jones

2012

A&A

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Context. The properties of hydrogenated amorphous carbon (a-C:H) dust are known to evolve in response to the local conditions. Aims. We present an adaptable model for the determination of the optical properties of low-temperature, interstellar a-C:H grains that is based on the fundamental physics of their composition. Methods. The imaginary part of the refractive index, k, for a-C:H materials, from 50 eV to cm wavelengths, is derived and the real part, n, of the refractive index is then calculated using the Kramers-Kronig relations. Results. The formulated optEC (s) model allows a determination of the complex dielectric function, , and refractive index, m(n, k), for a-C:H materials as a continuous function the band gap, E g , which is shown to lie in the range −0.1 to 2.7 eV. We provide expressions that enable a determination of their optical constants and tabulate m(n, k, E g ) for 14 different values of E g . We explore the evolution of the likely extinction and emission behaviours of a-C:H grains and estimate the relevant transformation time-scales. Conclusions. With the optEC (s) model we are able to predict how the optical properties of an a-C:H dust component in the interstellar medium will evolve in response to, principally, the local interstellar radiation field. The evolution of a-C:H materials appears to be consistent with many dust extinction, absorption, scattering and emission properties, and also with H 2 molecule, daughter "PAH" and hydrocarbon molecule formation resulting from its photo-driven decomposition.

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“…1996) . \ -----'-ACAR (Zubko et al 1996) Figure 3. Absorption efficiencies divided by particle radius calculated for spheres in vacuum from the optical data obtained for the materials cel400 (sp2 content= 67%) and cell000 (sp2 content= 80%) compared with the results for other soot materials (Preibisch et al 1993;Zubko et al 1996) and glassy carbon (Edoh 1983) (left figure).…”

Section: Carbonaceous Solidsmentioning

confidence: 99%

“…The influence of the internal structure on the FIR behaviour of different carbon materials has been investigated by Rouleau & Martin (1991), Preibisch et al (1993), Koike et al (1994Koike et al ( ,1995, Menella et al (1995), Colangeli et al (1995), and Zubko et al (1996). These investigations are based on data from transmission spectroscopy.…”

Section: Carbonaceous Solidsmentioning

confidence: 99%

Laboratory Astrophysics of Circumstellar Dust

Henning

1999

Symp. - Int. Astron. Union

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Abstract. This paper summarizes laboratory investigations of stardust analogue materials with special emphasis on the spectroscopic behaviour of silicates and carbonaceous materials. The review will also deal with the identification of the observed features in the dust spectra of AGB stars. Introd uctionSmall solid particles form an important component of the circumstellar (CS) environment of AGB stars. Although they are only minor contributors to the total mass of the envelopes, they are of decisive importance for their thermal, dynamical, and chemical state. IR and submm /mm continuum radiation is produced by the thermalization of stellar light. The gas is heated through collisions between dust particles and the gas atoms and molecules. The momentum in the outflows is supplied by radiation pressure acting on dust grains and the collisional transfer of momentum to the gas. The surfaces of dust grains can act as catalytic sites for the formation of molecules. In the outer regions of the envelopes, dust grains play an important role for shielding the molecules from dissociative interstellar UV radiation and cosmic rays. AGB stars are the main sources of freshly nucleated interstellar grains. Therefore, these objects are important for the chemical evolution of grain populations in galaxies, whose properties influence the birth of the next generation of stars.A deeper understanding of the complex interplay between hydrodynamics, radiation transfer, and chemistry has to be based on a better knowledge of the microphysics of CS dust. Guided by IR spectroscopy, submm/rnm observations, and the analysis of stardust in primitive meteorites, laboratory astrophysics must contribute to the understanding of dust formation from the gas phase, the formation of molecules by surface reactions, and the optical behaviour of small solid particles. On the other hand, AGB star envelopes are interesting regions for the study of grain formation and molecular chemistry under rather extreme conditions, usually difficult to reprod uce in terrestrial laboratories.The review will mainly deal with the optical properties of stardust analogue materials. Without better optical data, the radiative transfer modelling of spectral energy distributions and the interpretation of absorption and emission features observed in the dust spectra of AGB stars will remain ambiguous. 221of use, available at https://www.cambridge.org/core/terms. https://doi

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Optical constants of cosmic carbon analogue grains — I. Simulation of clustering by a modified continuous distribution of ellipsoids

Cited by 520 publications

References 1 publication

Variations on a theme – the evolution of hydrocarbon solids (Corrigendum)

Variations on a theme – the evolution of hydrocarbon solids (Corrigendum)

Variations on a theme – the evolution of hydrocarbon solids

Laboratory Astrophysics of Circumstellar Dust

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