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

Otsuka, Masaaki; Kemper, F.; Hyung, Siek; Sargent, B.; Meixner, Margaret; Tajitsu, Akito; Yanagisawa, K.

doi:10.1088/0004-637x/764/1/77

Cited by 40 publications

(45 citation statements)

References 87 publications

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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

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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Section: Interstellar Abundancesmentioning

confidence: 97%

Interstellar fullerene compounds and diffuse interstellar bands

Omont

2016

A&A

103

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“…Furthermore, in addition to other species, SiO and SO 2 have been recently identified toward the middle-aged PN M2-48 . Perhaps even more remarkable has been the recent discovery of C 60 in a few planetary nebulae (e.g., Cami et al 2010;García-Hernández et al 2010Otsuka et al 2013). Clearly, the molecular portfolio of planetary nebulae continues to grow.…”

Section: Introductionmentioning

confidence: 99%

New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C₆₀?

Schmidt

Ziurys

2017

ApJ

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New detections of CCH have been made toward nine planetary nebulae (PNe), including K4-47, K3-58, K3-17, M3-28, and M4-14. Measurements of the N = 1 → 0 and N = 3 → 2 transitions of this radical near 87 and 262 GHz were carried out using the new 12 m and the Sub-Millimeter Telescope (SMT) of the Arizona Radio Observatory (ARO). The presence of fine and/or hyperfine structure in the spectra aided in the identification. CCH was not observed in two PNe which are sources of C 60 . The planetary nebulae with positive detections represent a wide range of ages and morphologies, and all had previously been observed in HCN and HNC. Column densities for CCH in the PNe, determined from radiative transfer modeling, were N tot (CCH) ∼ 0.2-3.3 × 10 15 cm −2 , corresponding to fractional abundances with respect to H 2 of f ∼ 0.2-47 × 10 −7 . The abundance of CCH was found to not vary significantly with kinematic age across a time span of ∼10,000 years, in contrast to predictions of chemical models. CCH appears to be a fairly common constituent of PNe that are carbon-rich, and its distribution may anti-correlate with that of C 60 . These results suggest that CCH may be a product of C 60 photodestruction, which is known to create C 2 units. The molecule may subsequently survive the PN stage and populate diffuse clouds. The distinct, double-horned line profiles for CCH observed in K3-45 and M3-28 indicate the possible presence of a bipolar flow oriented at least partially toward the line of sight.

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“…We refer to the results by Georgiev (2009) for IC418 andOtsuka et al (2013) for M1-11. Since there is no information on gas emission line fluxes, except for Hβ, the effective temperature T eff , and the distance d, we could not model Hen2-68 and K3-62 using Cloudy.…”

Section: Properties Of the Central Stars And The Nebulaementioning

confidence: 99%

“…However, the first confirmed detection of cosmic fullerenes was only recently reported by Cami et al (2010) in the C-rich planetary nebula (PN) Tc1. Since then, a plethora of papers reported the discovery of cosmic fullerenes in Galactic (García-Hernández et al 2010Otsuka et al 2013;Zhang & Kwok 2011) and Large/Small Magellanic PNe ⋆ E-mail:otsuka@asiaa.sinica.edu.tw (García-Hernández et al 2010, Galactic asymptotic giant branch (AGB) stars ), H-poor R Coronae Borealis (R CrB) stars (García-Hernández et al 2011b;Clayton et al 2011), reflection nebulae (Sellgren et al 2010;Peeters et al 2012), a binary XX Oph star (Evans et al 2012), and YSOs (Roberts et al 2012). While the number of fullerene detections is increasing, the formation process and the excitation mechanism of fullerenes in evolved stars are the subject of active research.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, we found the 17.4 and 18.9 µm C 60 bands in the Spitzer/IRS SH spectrum of IC418; Morisset et al (2012) reported the C 60 detection in ISO spectra. We compare the Spitzer, AKARI, and ISO mid-IR spectra of these objects and previously known fullerene-containing PNe M1-11 (Otsuka et al 2013), M1-12, M1-20 (García-Hernández et al 2010), and Tc1 (Cami et al 2010) to the properties of the central stars and the other dust features such as the 3.3 and the 6-9 µm PAH bands, the broad 11 µm and 30 µm features, which are frequently seen in C 60 PNe. Moreover, we construct photo-ionization models using Cloudy (Ferland et al 1998) to derive the physical properties of the central stars and the nebulae of the eleven PNe in our sample.…”

Section: Introductionmentioning

confidence: 99%

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Physical Properties of Fullerene-containing Galactic Planetary Nebulae

Otsuka¹,

Kemper²,

Cami³

et al. 2014

Proceedings of the Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments — PoS(LCDU2013)

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We searched the Spitzer Space Telescope data archive for Galactic planetary nebulae (PNe), that show the characteristic 17.4 and 18.9 µm features due to C 60 , also known as buckminsterfullerene. Out of 338 objects with Spitzer/IRS data, we found eleven C 60 -containing PNe, six of which (Hen2-68, IC2501, K3-62, M1-6, M1-9, and SaSt2-3) are new detections, not known to contain C 60 prior to this work. The strongest 17.4 and 18.9 µm C 60 features are seen in Tc 1 and SaSt 2-3, and these two sources also prominently show the C 60 resonances at 7.0 and 8.5 µm. In the other nine sources, the 7.0 and 8.5 µm features due to C 60 are much weaker. We analyzed the spectra, along with ancillary data, using the photo-ionization code CLOUDY to establish the atomic line fluxes, and determine the properties of the radiation field, as set by the effective temperature of the central star. In addition, we measured the infrared spectral features due to dust grains. We find that the Polycyclic Aromatic Hydrocarbon (PAH) profile over 6-9 µm in these C 60 -bearing carbon-rich PNe is of the more chemically-processed class A. The intensity ratio of 3.3 µm to 11.3 µm PAH indicates that the number of C-atoms per PAH in C 60 -containing PNe is small compared to that in non-C 60 PNe. The Spitzer spectra also show broad dust features around 11 and 30 µm. Analysis of the 30-µm feature shows that it is strongly correlated with the continuum, and we propose that a single carbon-based carrier is responsible for both the continuum and the feature. The strength of the 11-µm feature is correlated to the temperature of the dust, suggesting that it is at least partially due to a solid-state carrier. The chemical abundances of C 60 -containing PNe can be explained by AGB nucleosynthesis models for initially 1.5-2.5 M ⊙ stars with Z=0.004. We plotted the locations of C 60 -containing PNe on a face-on map of the Milky Way and we found that most of these PNe are outside the solar circle, consistent with low metallicity values. Their metallicity suggests that the progenitors are an older population.

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

Cited by 40 publications

References 87 publications

Interstellar fullerene compounds and diffuse interstellar bands

Interstellar fullerene compounds and diffuse interstellar bands

New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C₆₀?

Physical Properties of Fullerene-containing Galactic Planetary Nebulae

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

Cited by 40 publications

References 87 publications

Interstellar fullerene compounds and diffuse interstellar bands

Interstellar fullerene compounds and diffuse interstellar bands

New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C60?

Physical Properties of Fullerene-containing Galactic Planetary Nebulae

Contact Info

Product

Resources

About

New Identifications of the CCH Radical in Planetary Nebulae: A Connection to C₆₀?