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Herschel/HIFI obser...
Herschel/HIFI observations of O-rich AGB stars: molecular inventory
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- Justtanont, Kay, 1965 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Khouri, T. (författare)
- Universiteit Van Amsterdam,University of Amsterdam
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- Maercker, Matthias, 1979 (författare)
- Universität Bonn,University of Bonn,European Southern Observatory (ESO)
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- Alcolea, J. (författare)
- Observatorio Astronómico Nacional (OAN),Spanish National Observatory (OAN)
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- Decin, L. (författare)
- Katholieke Universiteit Leuven,Universiteit Van Amsterdam,University of Amsterdam
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- Olofsson, Hans, 1952 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Schöier, Fredrik, 1969 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Bujarrabal, V. (författare)
- Observatorio Astronómico Nacional (OAN),Spanish National Observatory (OAN)
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- Marston, A. P. (författare)
- European Space Astronomy Centre (ESAC)
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- Teyssier, D. (författare)
- European Space Astronomy Centre (ESAC)
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Cernicharo, J. (författare)
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- Dominik, C. (författare)
- Radboud Universiteit,Radboud University,Universiteit Van Amsterdam,University of Amsterdam
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- de Koter, A. (författare)
- Universiteit Van Amsterdam,University of Amsterdam
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- Melnick, G. J. (författare)
- Harvard-Smithsonian Center for Astrophysics
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- Menten, K. M. (författare)
- Max Planck Gesellschaft zur Förderung der Wissenschaften e.V. (MPG),Max Planck Society for the Advancement of Science (MPG)
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- Neufeld, D. A. (författare)
- Johns Hopkins University
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- Planesas, P. (författare)
- Atacama Large Millimeter-submillimeter Array (ALMA),Observatorio Astronómico Nacional (OAN),Spanish National Observatory (OAN)
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- Schmidt, M. (författare)
- Polish Academy of Sciences
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- Szczerba, R. (författare)
- Polish Academy of Sciences
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- Waters, R. (författare)
- Universiteit Van Amsterdam,University of Amsterdam,Katholieke Universiteit Leuven
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(creator_code:org_t)
- 2012-01-24
- 2012
- Engelska.
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 537, s. Article Number: A144 -
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Aims. Spectra, taken with the heterodyne instrument, HIFI, aboard the Herschel Space Observatory, of O-rich asymptotic giant branch (AGB) stars which form part of the guaranteed time key program HIFISTARS are presented. The aim of this program is to study the dynamical structure, mass-loss driving mechanism, and chemistry of the outflows from AGB stars as a function of chemical composition and initial mass. Methods. We used the HIFI instrument to observe nine AGB stars, mainly in the H2O and high rotational CO lines. We investigate the correlation between line luminosity, line ratio and mass-loss rate, line width and excitation energy. Results. A total of nine different molecules, along with some of their isotopologues have been identified, covering a wide range of excitation temperature. Maser emission is detected in both the ortho-and para-H2O molecules. The line luminosities of ground state lines of ortho- and para-H2O, the high-J CO and NH3 lines show a clear correlation with mass-loss rate. The line ratios of H2O and NH3 relative to CO J = 6-5 correlate with the mass-loss rate while ratios of higher CO lines to the 6-5 is independent of it. In most cases, the expansion velocity derived from the observed line width of highly excited transitions formed relatively close to the stellar photosphere is lower than that of lower excitation transitions, formed farther out, pointing to an accelerated outflow. In some objects, the vibrationally excited H2O and SiO which probe the acceleration zone suggests the wind reaches its terminal velocity already in the innermost part of the envelope, i.e., the acceleration is rapid. Interestingly, for R Dor we find indications of a deceleration of the outflow in the region where the material has already escaped from the star.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- winds
- infrared: stars
- giant branch stars
- stars: AGB and post-AGB
- red supergiant stars
- hifi
- rotational line-profiles
- w-hydrae
- water-vapor
- stars: late-type
- mass-loss history
- circumstellar matter
- line: identification
- emission
- circumstellar envelopes
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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Till lärosätets databas
- Av författaren/redakt...
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Justtanont, Kay, ...
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Khouri, T.
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Maercker, Matthi ...
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Alcolea, J.
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Decin, L.
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Olofsson, Hans, ...
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visa fler...
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Schöier, Fredrik ...
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Bujarrabal, V.
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Marston, A. P.
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Teyssier, D.
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Cernicharo, J.
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Dominik, C.
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de Koter, A.
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Melnick, G. J.
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Menten, K. M.
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Neufeld, D. A.
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Planesas, P.
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Schmidt, M.
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Szczerba, R.
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Waters, R.
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