The 30 Micron Emission Band in Carbon-rich Pre--Planetary Nebulae

Omont, A.; Moseley, S. H.; Cox, P.; Glaccum, W.; Casey, S. C.; Forveille, T.; Chan, K. L.; Szczerba, R.; Loewenstein, R. F.; Harvey, P. M.; Kwok, Sun

doi:10.1086/176534

Cited by 74 publications

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“…Spectra of carbon-rich stars show two clear dust features peaking at about 11.2 and 30 Jlm whose strength increases as a function of optical depth (see, e.g., Omont et al 1995). The 11.3 Jlm feature has been attributed to SiC grains (see Mutschke et al 1998b), whereas the 30 Jlm feature has been identified with MgS (see .…”

Section: Stardust Materials -An Overviewmentioning

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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Section: Stardust Materials -An Overviewmentioning

confidence: 99%

Laboratory Astrophysics of Circumstellar Dust

Henning

1999

Symp. - Int. Astron. Union

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“…This "30" µm feature was first discovered in the far-IR spectra of CW Leo, IC 418 and NGC 6572 by Forrest et al (1981). Since then this feature has been detected in a wide range of carbon-rich evolved objects from intermediate mass loss C-stars (Yamamura et al 1998) to post-AGBs and PNe (Omont 1993;Cox 1993;Omont et al 1995;Jiang et al 1999;Szczerba et al 1999, see also Chapter 5). The feature is commonly found in C-rich post-AGBs and PNe however with varying band shapes and varying feature to continuum ratios (Goebel & Moseley 1985;Waters et al 2000;Hrivnak et al 2000;Volk et al 2002) Goebel & Moseley (1985 proposed solid magnesium sulfide (MgS) as the possible carrier of the "30" µm feature.…”

Section: Introductionmentioning

confidence: 97%

“…Lastly, these sources exhibit a strong, broad feature between 23−45 µm (Omont et al 1995;Szczerba et al 1997;Hrivnak et al 2000), called the "30" µm feature. The carrier of the "30" µm feature is identified with magnesium sulfide (MgS) (see Chapter 6 and references therein).…”

Section: Introductionmentioning

confidence: 99%

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confidence: 97%

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Infrared light on the composition of the dust surrounding carbon-rich stars

Hony¹

2003

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Alle rechten voorbehouden. Niets uit deze uitgave mag worden verveelvoudigd, opgeslagen in een geautomatiseerd gegevensbestand, of openbaar gemaakt, in enige vorm of op enige wijze, hetzij elektronisch, mechanisch, door fotokopieën, opnamen of enige andere manier, zonder voorafgaande schriftelijke toestemming van de uitgever. PrefaceMy first contact with astrophysics was during the introductory astronomy lectures taught by Ed van den Heuvel. From this very first moment I have been captured by a certain charm present throughout astrophysics. Of course the beauty of simplicity, to reduce any given system to its essentials, can be found in astrophysics and physics alike. However, the charm of astrophysics lies also in a totally different beauty. The beauty to do things in a clumsy, impractical way. For astronomy is a science with a history. In every corner of astronomy you find tantalising relics: habits, methods and units inherited from the past. They range from 'O Be A Fine Girl, Kiss Me' to plotting-axes that run the "wrong" way . Of course such silly details sometimes make me want to bang my head on the table, especially when converting ergs/cm 2 /s/Å/sr to Jansky again and taking again more than three tries to get it right. But still, the fact that we have to use the observations from 1987 to study supernova 1987a, gives another dimension to the field.On top of these charms, the study of the stars never fails to trigger a slight surprise in me. The same surprise that you will hear in the voice of non-astronomers: "How can we learn so much about the stars, when they are so far away and all you get is a little bit of light?".After finishing undergraduate astronomy it was very clear to me that I was trained for doing research. I am happy that Rens Waters and Xander Tielens asked me to do a research project under their supervision. That research has resulted in this thesis. I have certainly received a lot of support while doing my research and this is the place where I would like to express my gratitude.First of all, I want to thank Xander and Rens for allowing me the independence I need to work well. Rens; your enthusiasm has often kept me going when I; after weeks of staring; could not find anything interesting anymore in the things that I was doing. Xander, I have enjoyed your practical approach and your encyclopedic knowledge of solid-state physics and literature. I will never forget that time when you took a paper with a only few references scribbled on it from your notebook and handed it to me. You didn't remember what references these were but you said: "Maybe they are of some use." and they were.Words of thanks to Caroline and Els for the very fruitful collaborations that we have had. We started our PhD projects around the same time and I have learned much from observing the way you both handled things. I have always appreciated the support and the gentle way in which you could criticise me: "Maybe have another look at this?". Ciska, you also started your PhD project together with me and we shared office...

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“…Early in 1995, the 16-46 µm spectra were taken for five 21-µm emitters by KAO. It was found that the 30-µm feature is present in all of them, while the intensity of these two bands are not correlated (Omont et al, 1995). Later, from the ISO/SWS and Spitzer/IRS spectra, Hrivnak et al (2000Hrivnak et al ( , 2009) discovered new 30-µm emitters and quantitatively analyzed the percentage of the total IR flux emitted in the two features (see Table 1).…”

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confidence: 99%

The 21-μm and 30-μm circumstellar dust features in evolved C-rich objects

Jiang

Zhang

2010

Earth Planet Sp

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The 21-µm and 30-µm bands are the strongest dust emission features detected in evolved low-and intermediate-mass C-rich stars (i.e. asymptotic giant branch (AGB) stars, proto-planetary nebulae (PPNe), and planetary nebulae (PNe)). While the 21-µm feature is rare and exists only in the transient PPN phase, the 30-µm feature is more common and seen in the entire late stage of stellar evolution, from AGB to PPN and PN phases, as well as in the low-metallicity galaxies: the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC). The carriers of these features remain unidentified. All the 21-µm sources also emit in the 30-µm band, suggesting that their carriers may be somewhat related.

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The 30 Micron Emission Band in Carbon-rich Pre--Planetary Nebulae

Cited by 74 publications

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Laboratory Astrophysics of Circumstellar Dust

Laboratory Astrophysics of Circumstellar Dust

Infrared light on the composition of the dust surrounding carbon-rich stars

The 21-μm and 30-μm circumstellar dust features in evolved C-rich objects

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