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alpha Centauri A in...
alpha Centauri A in the far infrared - First measurement of the temperature minimum of a star other than the Sun
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- Liseau, René, 1949 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Montesinos, B. (författare)
- Centro de Astrobiologia (CAB)
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- Olofsson, Göran, 1944- (författare)
- Stockholms universitet,Institutionen för astronomi,Stockholm University
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Bryden, G. (författare)
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- Marshall, J. P. (författare)
- Universidad Autonoma de Madrid (UAM)
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- Ardila, D. R. (författare)
- European Space Astronomy Centre (ESAC),National Aeronautics and Space Administration (NASA),NASA Goddard Space Flight Center
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- Aran, A. B. (författare)
- European Southern Observatory Santiago,Max Planck Gesellschaft zur Förderung der Wissenschaften e.V. (MPG),Max Planck Society for the Advancement of Science (MPG)
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- Danchi, W. (författare)
- NASA Goddard Space Flight Center
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- del Burgo, C. (författare)
- Instituto Nacional de Astrofísica, Óptica y Electrońica (INAOE),National Institute of Astrophysics, Optics and Electronics (INAOE)
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- Eiroa, C. (författare)
- Universidad Autonoma de Madrid (UAM)
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- Ertel, S. (författare)
- Université Grenoble Alpes,Grenoble Alpes University
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- Fridlund, M. (författare)
- European Space Research and Technology Centre (ESA ESTEC)
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- Krivov, A. (författare)
- Friedrich-Schiller-Universität Jena,Friedrich Schiller University Jena
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- Pilbratt, G.L. (författare)
- European Space Research and Technology Centre (ESA ESTEC)
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- Roberge, A. (författare)
- NASA Goddard Space Flight Center
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- Thebault, P. (författare)
- Observatoire de Paris-Meudon
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- Wiegert, Joachim, 1985 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- White, G. J. (författare)
- STFC Rutherford Appleton Laboratory,Open University
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(creator_code:org_t)
- 2013-01-10
- 2013
- Engelska.
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 549
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http://publications.... (primary) (free)
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https://www.aanda.or...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Context. Chromospheres and coronae are common phenomena on solar-type stars. Understanding the energy transfer to these heated atmospheric layers requires direct access to the relevant empirical data. Study of these structures has, by and large, been limited to the Sun thus far.Aims. The region of the temperature reversal can be directly observed only in the far infrared and submillimetre spectral regime. We aim at determining the characteristics of the atmosphere in the region of the temperature minimum of the solar sister star alpha Cen A. As a bonus this will also provide a detailed mapping of the spectral energy distribution, i.e. knowledge that is crucial when searching for faint, Kuiper belt-like dust emission around other stars.Methods. For the nearby binary system alpha Cen, stellar parameters are known with high accuracy from measurements. For the basic model parameters T-eff, log g and [Fe/H], we interpolate stellar model atmospheres in the grid of Gaia/PHOENIX and compute the corresponding model for the G2 V star alpha Cen A. Comparison with photometric measurements shows excellent agreement between observed photospheric data in the optical and infrared. For longer wavelengths, the modelled spectral energy distribution is compared to Spitzer-MIPS, Herschel-PACS, Herschel-SPIRE, and APEX-LABOCA photometry. A specifically tailored Uppsala model based on the MARCS code and extending further in wavelength is used to gauge the emission characteristics of alpha Cen A in the far infared.Results. Similar to the Sun, the far infrared (FIR) emission of alpha Cen A originates in the minimum temperature region above the stellar photosphere in the visible. However, in comparison with the solar case, the FIR photosphere of alpha Cen A appears marginally cooler, T-min similar to T-160 (mu m) = 3920 +/- 375 K. Beyond the minimum near 160 mu m, the brightness temperatures increase, and this radiation very likely originates in warmer regions of the chromosphere of alpha Cen A.Conclusions. To the best of our knowledge, this is the first time a temperature minimum has been directly measured on a main-sequence star other than the Sun.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- solar chromosphere
- circumstellar matter
- binary-system
- atmosphere
- free absorption coefficient
- components
- submillimeter
- infrared
- stars: individual: alpha Cen
- camera
- model
- continuum
- stars: chromospheres
- stars: atmospheres
- millimeter
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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Till lärosätets databas
- Av författaren/redakt...
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Liseau, René, 19 ...
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Montesinos, B.
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Olofsson, Göran, ...
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Bryden, G.
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Marshall, J. P.
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Ardila, D. R.
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visa fler...
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Aran, A. B.
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Danchi, W.
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del Burgo, C.
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Eiroa, C.
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Ertel, S.
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Fridlund, M.
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Krivov, A.
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Pilbratt, G.L.
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Roberge, A.
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Thebault, P.
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Wiegert, Joachim ...
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White, G. J.
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visa färre...
- Om ämnet
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- NATURVETENSKAP
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Chalmers tekniska högskola
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Stockholms universitet