The 6.2 $\sf \mu{\rm m}$ band position in laboratory and astrophysical spectra: a tracer of the aliphatic to aromatic evolution of interstellar carbonaceous dust

Pino, T.; Dartois, E.; Cao, Ang; Carpentier, Y.; Chamaillé, T.; Vasquez, R. P.; Jones, A. P.; D’Hendecourt, L.; Bréchignac, Ph.

doi:10.1051/0004-6361:200809927

Cited by 127 publications

(133 citation statements)

References 59 publications

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“…In fact, observational evidence strongly suggests that carbon dust consists of hydrogenated amorphous carbon (HAC or a-C:H) materials that form around evolved stars, metamorphose there (e.g., Goto et al 2003) and further evolve in the ISM (e.g., Jones et al 1990;Pino et al 2008;Jones 2009). HAC material could also form directly into the ISM from the UV processing of ice mantles after leaving the dense medium as suggested by Greenberg et al (1995) or via direct accretion of carbon and hydrogen (e.g.…”

Section: The Nature Of Interstellar Carbon Grainsmentioning

confidence: 99%

The global dust SED: tracing the nature and evolution of dust with DustEM

Compiègne

Verstraete

Jones

et al. 2010

A&A

410

724

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The Planck and Herschel missions are currently measuring the far-infrared to millimeter emission of dust, which combined with existing IR data, will for the first time provide the full spectral energy distribution (SED) of the galactic interstellar medium dust emission, from the mid-IR to the mm range, with an unprecedented sensitivity and down to spatial scales ∼30 . Such a global SED will allow a systematic study of the dust evolution processes (e.g. grain growth or fragmentation) that directly affect the SED because they redistribute the dust mass among the observed grain sizes. The dust SED is also affected by variations of the radiation field intensity. Here we present a versatile numerical tool, DustEM, that predicts the emission and extinction of dust grains given their size distribution and their optical and thermal properties. In order to model dust evolution, DustEM has been designed to deal with a variety of grain types, structures and size distributions and to be able to easily include new dust physics. We use DustEM to model the dust SED and extinction in the diffuse interstellar medium at high-galactic latitude (DHGL), a natural reference SED that will allow us to study dust evolution. We present a coherent set of observations for the DHGL SED, which has been obtained by correlating the IR and HI-21 cm data. The dust components in our DHGL model are (i) polycyclic aromatic hydrocarbons; (ii) amorphous carbon and (iii) amorphous silicates. We use amorphous carbon dust, rather than graphite, because it better explains the observed high abundances of gas-phase carbon in shocked regions of the interstellar medium. Using the DustEM model, we illustrate how, in the optically thin limit, the IRAS/Planck HFI (and likewise Spitzer/Herschel for smaller spatial scales) photometric band ratios of the dust SED can disentangle the influence of the exciting radiation field intensity and constrain the abundance of small grains (a < ∼ 10 nm) relative to the larger grains. We also discuss the contributions of the different grain populations to the IRAS, Planck (and similarly to Herschel) channels. Such information is required to enable a study of the evolution of dust as well as to systematically extract the dust thermal emission from CMB data and to analyze the emission in the Planck polarized channels. The DustEM code described in this paper is publically available.

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Section: The Nature Of Interstellar Carbon Grainsmentioning

confidence: 99%

The global dust SED: tracing the nature and evolution of dust with DustEM

Compiègne

Verstraete

Jones

et al. 2010

A&A

410

724

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“…The intimate structures of the carriers of these different classes of AIBs are still unknown, although they are probably built on a polyaromatic skeleton spanning sizes from large molecules to small nanograins (Leger & Puget 1984;Allamandola et al 1985;Goto et al 2007;Sloan et al 2007;Pino et al 2008;Tielens 2008;Joblin & Tielens 2011;Li & Draine 2012;Carpentier et al 2012;Yang et al 2013).…”

Section: General Overviewmentioning

confidence: 99%

“…Soot samples were produced at the Institut des Sciences Moléculaires d'Orsay (France) using the setup Nanograins (Pino et al 2008;Carpentier et al 2012). In the setup, whose scheme is shown in Fig.…”

Section: Preparation Of Soot Filmsmentioning

confidence: 99%

VUV spectroscopy of carbon dust analogs: contribution to interstellar extinction

Gavilan

Alata

et al. 2016

A&A

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Context.A full spectral characterization of carbonaceous dust analogs is necessary to understand their potential as carriers of observed astronomical spectral signatures such as the ubiquitous UV bump at 217.5 nm and the far-ultraviolet (FUV) rise common to interstellar extinction curves. Aims. Our goal is to study the spectral properties of carbonaceous dust analogs from the FUV to the mid-infrared (MIR) domain. We seek in particular to understand the spectra of these materials in the FUV range, for which laboratory studies are scarce. Methods. We produced analogs to carbonaceous interstellar dust encountered in various phases of the interstellar medium: amorphous hydrogenated carbons (a-C:H), for carbonaceous dust observed in the diffuse interstellar medium, and soot particles, for the polyaromatic component. Analogs to a-C:H dust were produced using a radio-frequency plasma reactor at low pressures, and soot nanoparticles films were produced in an ethylene (C 2 H 4 ) flame. We measured transmission spectra of these thin films (thickness <100 nm) in the far-ultraviolet (190−250 nm) and in the vacuum-ultraviolet (VUV; 50−190 nm) regions using the APEX chamber at the DISCO beam line of the SOLEIL synchrotron radiation facility. These were also characterized through infrared microscopy at the SMIS beam line. Results. We successfully measured the transmission spectra of these analogs from λ = 1 μm to 50 nm. From these, we extracted the laboratory optical constants via Kramers-Kronig inversion. We used these constants for comparison to existing interstellar extinction curves. Conclusions. We extend the spectral measurements of these types of carbonaceous analogs into the VUV and link the spectral features in this range to the 3.4 μm band. We suggest that these two materials might contribute to different classes of interstellar extinction curves.

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“…It is assumed that these are carbonaceous structures, with a mixture of hybridizations (sp 3 , sp 2 and sp 1 ) of carbon atoms, such as hydrogenated amorphous carbon (HAC) materials which contain a fraction of hydrogen. Nowadays, HAC materials have been considered as a realistic model for interstellar carbon dust (e.g., Jones et al 1990; Dartois et al 2004Dartois & Muñoz-Caro 2007;Pino et al 2008). In astronomical observations in MIR range, the C-H stretching vibration band at 3.4 μm and the C-H deformation bands at 6.85 and 7.25 μm are evidences of the existence of HAC materials in the diffuse ISM (Chiar et al 2000;Pendleton & Allamandola 2002).…”

Section: Introductionmentioning

confidence: 99%

UV irradiated hydrogenated amorphous carbon (HAC) materials as a carrier candidate of the interstellar UV bump at 217.5 nm

Gadallah

Mutschke

Jäger

2011

A&A

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Context. Hydrogenated amorphous carbon (HAC) materials have been considered as a laboratory analog of cosmic carbonaceous nanoparticles in the interstellar medium (ISM). In the diffuse ISM, UV radiation can modify the electronic and atomic structure of HAC materials. Aims. Studying structural and optical properties of HAC materials in correlation with UV processing is very important to understand more clearly the effect of the UV radiation on carbonaceous dust grains in the diffuse ISM. This scenario can explain some astronomical spectral features such as the interstellar UV bump at 4.6 μm −1 . Methods. Laser ablation has been used to produce nano-sized HAC materials which are subsequently irradiated by strong UV doses in a high vacuum. Transmission electron microscope images and spectroscopic analyses show the evolution of the internal structure of the material with the UV irradiation. Results. It is found that hydrogen content and the sp 3 /sp 2 hybridization ratio decrease with the UV irradiation. The graphene layers become longer in processed materials. Also, graphitic fibers are observed in modified materials. The variation in the internal structure leads to dramatic changes in the spectral properties in the FUV-VIS range. The UV irradiation of HAC materials, coresponding to 21-33% of the average dose of the UV radiation in diffuse ISM, has produced a new band centered at 4.6 μm −1 (217.5 nm). Conclusions. Consequently, these results confirm for the first time the suggestion by Mennella et al. (1996) that irradiated HAC materials might be considered the carrier of the interstellar UV bump at 4.6 μm −1 . However, so far the amount of carbon needed to produce the interstellar 4.6 μm −1 band is higher than that available for interstellar carbon dust grains. So the ideal structure of irradiated HAC materials that would produce a band of sufficient strength is not yet clear for the interstellar dust.

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The 6.2 $\sf \mu{\rm m}$ band position in laboratory and astrophysical spectra: a tracer of the aliphatic to aromatic evolution of interstellar carbonaceous dust

Cited by 127 publications

References 59 publications

The global dust SED: tracing the nature and evolution of dust with DustEM

The global dust SED: tracing the nature and evolution of dust with DustEM

VUV spectroscopy of carbon dust analogs: contribution to interstellar extinction

UV irradiated hydrogenated amorphous carbon (HAC) materials as a carrier candidate of the interstellar UV bump at 217.5 nm

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