Carbonaceous molecules in the oxygen-rich circumstellar environment of binary post-AGB stars

Gielen, C.; Cami, J.; Bouwman, J.; Peeters, E.; Min, M.

doi:10.1051/0004-6361/201117961

Cited by 71 publications

(84 citation statements)

References 72 publications

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“…In our own Milky Way, these C 60 infrared features were recently detected in five PNe, including Tc1, M1-12, M1-20, K3-54, and M1-60 (Cami et al 2010;García-Hernández et al 2010), a C-rich PPN (IRAS 01005+7910; Zhang & Kwok 2011), and two O-rich post-AGB stars (IRAS 06338+5333 and HD52961; Gielen et al 2011). In Figure 8, we show the IRS spectrum of M1-12 compared to M1-11.…”

Section: μM Emission Due To C 60 Fullerenesmentioning

confidence: 78%

“…Recent Spitzer/IRS studies show that fullerenes C 60 are detected in several young PNe, a proto-PN (PPN), and two post asymptotic giant branch (post-AGB) stars in the Milky Way (Cami et al 2010;García-Hernández et al 2010;Zhang & Kwok 2011;Gielen et al 2011) and also in a handful of young PNe in the Magellanic Clouds (García-Hernández et al 2011a;Bernard-Salas et al 2012). The detection cases are increasing, however, the excitation and formation mechanism is still unclear (e.g., Cami et al 2011;García-Hernández 2012).…”

Section: Introductionmentioning

confidence: 99%

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The Detection of C60 in the Well-Characterized Planetary Nebula M1-11

Otsuka

Kemper

Hyung

et al. 2013

ApJ

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We performed multiwavelength observations of the young planetary nebula (PN) M1-11 and obtained its elemental abundances, dust mass, and the evolutionary status of the central star. The AKARI/IRC, VLT/VISIR, and Spitzer/IRS spectra show features due to carbon-rich dust, such as the 3.3, 8.6, and 11.3 μm features due to polycyclic aromatic hydrocarbons (PAHs), a smooth continuum attributable to amorphous carbon, and the broad 11.5 and 30 μm features often ascribed to SiC and MgS, respectively. We also report the presence of an unidentified broad feature at 16-22 μm, similar to the feature found in Magellanic Cloud PNe with either C-rich or O-rich gas-phase compositions. We identify for the first time in M1-11 spectral lines at 8.5 (blended with PAH), 17.3, and 18.9 μm that we attribute to the C 60 fullerene. This identification is strengthened by the fact that other Galactic PNe in which fullerenes are detected have similar central stars, similar gas-phase abundances, and a similar dust composition to M1-11. The weak radiation field due to the relatively cool central stars in these PNe may provide favorable conditions for fullerenes to survive in the circumstellar medium. Using the photoionization code Cloudy, combined with a modified blackbody, we have fitted the ∼0.1-90 μm spectral energy distribution (SED) and determined the dust mass in the nebula to be ∼3.5 × 10 −4 M . Our chemical abundance analysis and SED model suggest that M1-11 is perhaps a C-rich PN with C/O ratio in the gas phase of +0.19 dex, and that it evolved from a 1-1.5 M star.

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Section: μM Emission Due To C 60 Fullerenesmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

The Detection of C60 in the Well-Characterized Planetary Nebula M1-11

Otsuka

Kemper

Hyung

et al. 2013

ApJ

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“…In this context, HD 52961 is an interesting target for a similar study to the one presented here. The primary in this evolved binary also displays an extreme depletion pattern and the infrared spectrum indicates the presence of PAH molecules, fullerenes, and CO 2 (Gielen et al 2011b). However, silicate emission is also detected.…”

Section: Discussionmentioning

confidence: 92%

Amorphous carbon in the disk around the post-AGB binary HR 4049

Acke

Degroote

Lombaert

et al. 2013

A&A

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Context. Infrared spectroscopy has been extensively used to determine the mineralogy of circumstellar dust. The identification of dust species with featureless opacities, however, is still ambiguous. Here we present a method to lift the degeneracy using the combination of infrared spectroscopy and interferometry. Aims. The binary post-AGB star HR 4049 is surrounded by a circumbinary disk viewed at a high inclination angle. Apart from gaseous emission lines and molecular emission bands of polycyclic aromatic hydrocarbons (PAH), diamonds, and fullerenes, the 2-25 μm infrared spectrum is featureless. The goal of the paper is to identify the dust species responsible for the smooth spectrum. Methods. We gathered high-angular-resolution measurements in the near-and mid-infrared with the VLTI interferometric instruments AMBER and MIDI. The data set is expanded with archival Geneva optical photometry, ISO-SWS and Spitzer-IRS infrared spectroscopy, and VISIR N-band images and spectroscopy. We computed a grid of radiative-transfer models of the circumbinary disk of HR 4049 using the radiative-transfer code MCMax. We searched for models that provide good fits simultaneously to all available observations. Results. We find that the variable optical extinction towards the primary star is consistent with the presence of very small (0.01 μm) iron-bearing dust grains or amorphous carbon grains. The combination of the interferometric constraint on the disk extent and the shape of the infrared spectrum points to amorphous carbon as the dominant source of opacity in the circumbinary disk of HR 4049. The disk is optically thick to the stellar radiation in the radial direction. At infrared wavelengths it is optically thin. The PAH emission is spatially resolved in the VISIR data and emanates from a region with an extent of several hundreds of AU, with a projected photocenter displacement of several tens of AU from the disk center. The PAHs most likely reside in a bipolar outflow. Conclusions. Dust species with featureless opacity curves, such as metallic iron and amorphous carbon, can be identified by combining infrared spectroscopy and high-angular-resolution measurements. In essence, this is because the temperatures of the dust species are notably different at the same physical distance to the star.

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“…Long after the initial proposed identification of C + 60 in the ISM by Foing & Ehrenfreud (1994) taking advantage of the laboratory spectrum of Fulara et al (1993a), the presence of C 60 + has been recently confirmed in diffuse interstellar clouds and the presence of C 60 previously in various environments as described by Cami (2014) and Berné et al (2015b), among others: various types of carbon-rich planetary nebulae (Cami et al 2010;García-Hernández et al 2010, 2011aGielen et al 2011, Otsuka et al 2013); a single pre-planetary nebula (Zhang & Kwok 2011); various interstellar environments (Rubin et al 2011;Peeters et al 2012;Boersma et al 2012), including reflection nebulae such as NGC 7023 (Sellgren et al 2007(Sellgren et al , 2010Berné & Tielens 2012) and young stellar objects (Roberts et al 2012).…”

Section: Interstellar Abundancesmentioning

confidence: 97%

Interstellar fullerene compounds and diffuse interstellar bands

Omont

2016

A&A

100

103

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Recently, the presence of fullerenes in the interstellar medium (ISM) has been confirmed and new findings suggest that these fullerenes may possibly form from polycyclic aromatic hydrocarbons (PAHs) in the ISM. Moreover, the first confirmed identification of two strong diffuse interstellar bands (DIBs) with the fullerene, C + 60 , connects the long standing suggestion that various fullerenes could be DIB carriers. These new discoveries justify reassessing the overall importance of interstellar fullerene compounds, including fullerenes of various sizes with endohedral or exohedral inclusions and heterofullerenes (EEHFs). The phenomenology of fullerene compounds is complex. In addition to fullerene formation in grain shattering, fullerene formation from fully dehydrogenated PAHs in diffuse interstellar clouds could perhaps transform a significant percentage of the tail of low-mass PAH distribution into fullerenes including EEHFs. But many uncertain processes make it extremely difficult to assess their expected abundance, composition and size distribution, except for the substantial abundance measured for C + 60 . EEHFs share many properties with pure fullerenes, such as C 60 , as regards stability, formation/destruction and chemical processes, as well as many basic spectral features. Because DIBs are ubiquitous in all lines of sight in the ISM, we address several questions about the interstellar importance of various EEHFs, especially as possible carriers of diffuse interstellar bands. Specifically, we discuss basic interstellar properties and the likely contributions of fullerenes of various sizes and their charged counterparts such as C + 60 , and then in turn: 1) metallofullerenes; 2) heterofullerenes; 3) fulleranes; 4) fullerene-PAH compounds; 5) H 2 @C 60 . From this reassessment of the literature and from combining it with known DIB line identifications, we conclude that the general landscape of interstellar fullerene compounds is probably much richer than heretofore realized. EEHFs, together with pure fullerenes of various sizes, have many properties necessary to be suitably carriers of DIBs: carbonaceous nature; stability and resilience in the harsh conditions of the ISM; existing with various heteroatoms and ionization states; relatively easy formation; few stable isomers; spectral lines in the right spectral range; various and complex energy internal conversion; rich Jahn-Teller fine structure. This is supported by the first identification of a DIB carrier as C + 60 . Unfortunately, the lack of any precise information about the complex optical spectra of EEHFs and most pure fullerenes other than C 60 and about their interstellar abundances still precludes definitive assessment of the importance of fullerene compounds as DIB carriers. Their compounds could significantly contribute to DIBs, but it still seems difficult that they are the only important DIB carriers. Regardless, DIBs appear as the most promising way of tracing the interstellar abundances of various fullerene compounds if the breakthr...

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Carbonaceous molecules in the oxygen-rich circumstellar environment of binary post-AGB stars

Cited by 71 publications

References 72 publications

The Detection of C60 in the Well-Characterized Planetary Nebula M1-11

The Detection of C60 in the Well-Characterized Planetary Nebula M1-11

Amorphous carbon in the disk around the post-AGB binary HR 4049

Interstellar fullerene compounds and diffuse interstellar bands

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