Infrared Spectroscopy of Dust in the Diffuse Interstellar Medium toward Cygnus OB2 No. 12

Whittet, D. C. B.; Boogert, A. C. A.; Gerakines, Perry A.; Schütte, W. A.; Tielens, A. G. G. M.; Graauw, Th. de; Prusti, T.; Dishoeck, E. F. van; Wesselius, P. R.; Wright, Cameron H. G.

doi:10.1086/304914

Cited by 154 publications

(177 citation statements)

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“…In the diffuse ISM (DISM), a possible identification was made by Whittet et al (1997) who detected a weak feature near 2.75 μm in IR spectra of dust towards Cygnus OB2 No. 12.…”

Section: Discussionmentioning

confidence: 99%

“…12. Figure 2 in Whittet et al (1997), compares the spectra of this source obtained with the Kuiper Airbone Obervatory (KAO) by Knacke et al (1985), to those obtained with ISO at two resolving powers R (R = 200 and 400). The three spectra reported there exhibit a feature centered at ∼2.75 μm.…”

Section: Discussionmentioning

confidence: 99%

“…Tentative detections have been reported, but not confirmed for the diffuse ISM by Whittet et al (1997) via the OH stretching mode at ∼2.75 μm. Timmermann & Larson (1993) observed a sharp absorption edge at 2.7 μm in the near IR spectrum of SN 1987A.…”

Section: Introductionmentioning

confidence: 93%

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Hydroxyl radical production and storage in analogues of amorphous interstellar silicates: a possible “wet” accretion phase for inner telluric planets

Djouadi

Robert

d’Hendecourt

et al. 2011

A&A

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Context. Interstellar silicate grains are thought to be amorphized by interaction with high-and low-energy particle interactions in astrophysical environments. In addition, low energy (a few keV) particles will implant atoms within the grains. Aims. In this paper we experimentally investigate the consequence of the implantation of H + at low irradiation energies into analogues of interstellar silicate grains, and look for the formation of hydroxyl radicals within the silicate matrix. Methods. Thin amorphous silicate films (∼100 nm) were sequentially irradiated with H + ions at low energies (3.5, 2.5 and then 1.5 keV) ensuring an implantation of the ions through the full depth of the films. The fluences used, 3× 10 16 , 10 17 and 3× 10 17 H + /cm 2 , are compatible with those expected in shocks in the interstellar medium. We used infrared spectroscopy to monitor and quantify the OH band evolution after irradiation. In order to distinguish the newly formed OH groups from those originating from unavoidable atmospheric contamination, the D/H depth ratios were measured with a NanoSIMS ion microprobe.Results. An increase in the OH band strength in the infrared spectra after irradiation reveals the formation of OH bonds within the irradiated silicate thin films. NanoSIMS measurements of the D/H signature in the region of ion implantation show that the newlyformed OH groups make up about 40% of the observed OH band in the IR, the rest are due to an atmospheric hydroxylation of the sample. Only about 2% of the incident ions lead to OH bond formation and, at most, the irradiated silicates retain about 3% of the incident protons as OH groups within their structure. Conclusions. Our laboratory experimental simulations show a possible production and storage of hydroxyl radicals in amorphous laboratory silicates. In the astrophysical context, such OH radicals, strongly bonded to pre-accretion material, could constitute a non negligible reservoir of -OH, thus water. These experimental results allow us to revisit and reinstate the hypothesis of a possible "wet" accretion of the telluric planets early in the history of the formation of the Solar System.

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“…In the diffuse ISM (DISM), a possible identification was made by Whittet et al (1997) who detected a weak feature near 2.75 μm in IR spectra of dust towards Cygnus OB2 No. 12.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Hydroxyl radical production and storage in analogues of amorphous interstellar silicates: a possible “wet” accretion phase for inner telluric planets

Djouadi

Robert

d’Hendecourt

et al. 2011

A&A

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“…An extremely important component of the carbonaceous matter in the diffuse interstellar medium (ISM) could be the hydrogenated amorphous carbon (HAC) material. In the Milky Way, these materials have been observed at the 3.4 μm stretching band along many lines of sight in the local diffuse ISM (Pendleton et al 1994;Whittet et al 1997;Pendleton & Allamandola 2002) and along lines of sight of Sgr A*, GCS 3 and GCS 4 toward the galactic center (Chiar et al 2000(Chiar et al , 2002. They are also observed at 6.8 μm and 7.25 μm (C-H deformation bands) in Spitzer IRS extragalactic spectra in the diffuse ISM of many galaxies (Dartois & Muñoz-Caro 2007).…”

Section: Introductionmentioning

confidence: 91%

Mid-infrared spectroscopy of UV irradiated hydrogenated amorphous carbon materials

Gadallah

Mutschke

Jäger

2012

A&A

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Context. Mid-infrared (MIR) bands are characteristic for the short-range and medium-range structure of hydrogenated amorphous carbon (HAC) materials that exist in the interstellar medium (ISM) and are sensitive to processing in the harsh interstellar radiation field. Aims. We study the variability of the MIR features from the spectrum of non-processed to that of UV-processed HAC materials and compare them to spectra of interstellar carbonaceous materials. Methods. Nano-sized HAC materials produced by laser ablation were irradiated by vacuum-UV photons with doses comparable to those relevant for interstellar processing. They were subsequently analyzed by IR spectroscopy. Results. In the MIR range, the spectra of HAC materials show many absorption bands such as the sp 3 aliphatic ≡C-H stretching vibration at 3.03 μm, the sp 3 aliphatic -C-H stretching vibration at 3.4 μm and also the sp 3 aliphatic C-H bending vibration at both 6.85 μm and 7.25 μm. All these are recognizable bands of HAC materials. Other absorption bands such as the sp 2 aromatic =C-H stretching vibration at about 3.3 μm and the sp 2 -C=C stretching vibration close to 6.25 μm are observed. The HAC materials also possess bands which represent the aromatic out-of-plane bending at 11.65, 12.46 and 12.9 μm in addition to the aromatic -C-C-C in-plane bending at 15.87 μm. With UV irradiation, the mass absorption coefficient of the 3.03 μm band completely disappears and that of the aliphatic C-H bands (3.4, 6.85 and 7.25 μm) decreases. This reduction shows that the UV radiation destroys most of the aliphatic C-H bonds inside the HAC structure. On the other hand, the strength of the aromatic 6.2 μm band increases, which is evidence of the partial graphitization within UV-irradiated HAC materials. Because UV irradiation is not uniform, this band agrees well with the C-class PAH toward HD 100764. The C-H out-of-plane vibration bands are strongly affected by UV irradiation. Bands at 11.35, 12.14 and 12.64 μm (solo, duo and trio, respectively), which are found for PAHs of many interstellar spectra were observed partially and were compared to those of non-processed materials, in particular, those at 11.35 μm, which represent the aromatic structures. Conclusions. UV irradiation has a variable effect on both aliphatic and aromatic bands in the MIR region. The aliphatic C-H structure decreases while the aromatic C=C structure, which might lead to the graphitic colonies for PAHs, increases. UV irradiation has revealed solo, duo and trio bands that are relatively consistent with those of the A-and B-class PAHs.

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“…Observations have been made along a number of Galactic lines of sight, sampling the diffuse ISM toward the Galactic center and a number of reddened field stars and young stellar objects (YSOs), and the newly formed circumstellar dust in the protoplanetary nebula CRL 618 (Butchart et al 1986;McFadzean et al 1989;Adamson et al 1990; Lequeux & Jourdain de Muizon 1990;Sandford et al 1991;Pendleton et al 1994;Sandford et al 1995;Imanishi et al 1996;Whittet et al 1997;Chiar et al 1998Chiar et al , 2000Chiar et al , 2002Ishii et al 2002;Rawlings et al 2003). The 3.4 m feature has also been studied in the Murchison meteorite (Cronin & Pizzarello 1990;de Vries et al 1993).…”

Section: Introductionmentioning

confidence: 99%

Hydrocarbon Dust Absorption in Seyfert Galaxies and Ultraluminous Infrared Galaxies

Mason¹,

Wright²,

Pendleton³

et al. 2004

ApJ

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We present new spectroscopic observations of the 3.4 m absorption feature in the Seyfert galaxies NGC 1068 and NGC 7674 and the ultraluminous infrared galaxy IRAS 08572+3915. A signature of CÀH bonds in aliphatic hydrocarbons, the 3.4 m feature indicates the presence of organic material in Galactic and extragalactic dust. Here we compare the 3.4 m feature in all the galaxies in which it has been detected. In several cases, the signalto-noise ratio and spectral resolution permit a detailed examination of the feature profile, something which has rarely been attempted in extragalactic lines of sight. The 3.4 m band in these galaxies closely resembles that seen in the Galactic diffuse interstellar medium (ISM) and in newly formed dust in a protoplanetary nebula. The similarity implies a common carrier for the carbonaceous component of dust, and one which is resistant to processing in the interstellar and /or circumnuclear medium. We also examine the mid-IR spectrum of NGC 1068, because absorption bands in the 5-8 m region further constrain the chemistry of the 3.4 m band carrier. While weak features like those present in the mid-IR spectrum of diffuse dust toward the Galactic center would be undetectable in NGC 1068, the strong bands found in the spectra of many proposed dust analog materials are clearly absent, eliminating certain candidates and production mechanisms for the carrier. The absence of strong absorption features at 5-8 m is also consistent with the interpretation that the similarity in the 3.4 m feature in NGC 1068 to that in Galactic lines of sight reflects real chemical similarity in the carbonaceous dust.

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Infrared Spectroscopy of Dust in the Diffuse Interstellar Medium toward Cygnus OB2 No. 12

Cited by 154 publications

References 24 publications

Hydroxyl radical production and storage in analogues of amorphous interstellar silicates: a possible “wet” accretion phase for inner telluric planets

Hydroxyl radical production and storage in analogues of amorphous interstellar silicates: a possible “wet” accretion phase for inner telluric planets

Mid-infrared spectroscopy of UV irradiated hydrogenated amorphous carbon materials

Hydrocarbon Dust Absorption in Seyfert Galaxies and Ultraluminous Infrared Galaxies

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