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Herschel/PACS obser...
Herschel/PACS observations of the 69 mu m band of crystalline olivine around evolved stars
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Blommaert, J. A. D. L. (author)
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- de Vries, Bernhard L. (author)
- Stockholms universitet,Institutionen för astronomi,Katholieke University, Leuven, Belgium
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Waters, L. B. F. M. (author)
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Waelkens, C. (author)
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Min, M. (author)
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Van Winckel, H. (author)
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Molster, F. (author)
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Decin, L. (author)
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Groenewegen, M. A. T. (author)
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Barlow, M. (author)
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Garcia-Lario, P. (author)
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Kerschbaum, F. (author)
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Posch, Th (author)
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Royer, P. (author)
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Ueta, T. (author)
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Vandenbussche, B. (author)
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Van de Steene, G. (author)
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van Hoof, P. (author)
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(creator_code:org_t)
- 2014-05-20
- 2014
- English.
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 565, s. A109-
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https://www.aanda.or...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
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- Context. We present 48 Herschel/PACS spectra of evolved stars in the wavelength range of 67-72 mu m. This wavelength range covers the 69 mu m band of crystalline olivine (Mg-2 2xFe(2x)SiO4). The width and wavelength position of this band are sensitive to the temperature and composition of the crystalline olivine. Our sample covers a wide range of objects: from high mass-loss rate AGB stars (OH/IR stars, (M) over dot >= 10(-5) M-circle dot/yr), through post-AGB stars with and without circumbinary disks, to planetary nebulae and even a few massive evolved stars. Aims. The goal of this study is to exploit the spectral properties of the 69 mu m band to determine the composition and temperature of the crystalline olivine. Since the objects cover a range of evolutionary phases, we study the physical and chemical properties in this range of physical environments. Methods. We fit the 69 mu m band and use its width and position to probe the composition and temperature of the crystalline olivine. Results. For 27 sources in the sample, we detected the 69 mu m band of crystalline olivine (Mg(2-2x)Fe(2x)SiO4). The 69 mu m band shows that all the sources produce pure forsterite grains containing no iron in their lattice structure. The temperature of the crystalline olivine as indicated by the 69 mu m band, shows that on average the temperature of the crystalline olivine is highest in the group of OH/IR stars and the post-AGB stars with confirmed Keplerian disks. The temperature is lower for the other post-AGB stars and lowest for the planetary nebulae. A couple of the detected 69 mu m bands are broader than those of pure magnesium-rich crystalline olivine, which we show can be due to a temperature gradient in the circumstellar environment of these stars. The disk sources in our sample with crystalline olivine are very diverse. They show either no 69 mu m band, a moderately strong band, or a very strong band, together with a temperature for the crystalline olivine in their disk that is either very warm (similar to 600 K), moderately warm (similar to 200 K), or cold (similar to 120 K), respectively.
Subject headings
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Keyword
- stars: AGB and post-AGB
- circumstellar matter
- stars: winds
- outflows
- stars: evolution
- dust
- extinction
Publication and Content Type
- ref (subject category)
- art (subject category)
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- By the author/editor
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Blommaert, J. A. ...
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de Vries, Bernha ...
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Waters, L. B. F. ...
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Waelkens, C.
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Min, M.
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Van Winckel, H.
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show more...
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Molster, F.
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Decin, L.
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Groenewegen, M. ...
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Barlow, M.
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Garcia-Lario, P.
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Kerschbaum, F.
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Posch, Th
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Royer, P.
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Ueta, T.
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Vandenbussche, B ...
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Van de Steene, G ...
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van Hoof, P.
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show less...
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Stockholm University