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The adventure of ca...
The adventure of carbon stars : Observations and modeling of a set of C-rich AGB stars
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- Rau, G. (författare)
- Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
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- Hron, J. (författare)
- Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
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- Paladini, C. (författare)
- Univ Libre Bruxelles, Inst Astron & Astrophys, Blvd Triomphe CP 226, B-1050 Brussels, Belgium.
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- Aringer, B. (författare)
- Astron Observ Padova INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy.
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- Eriksson, Kjell (författare)
- Uppsala universitet,Teoretisk astrofysik
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- Marigo, P. (författare)
- Astron Observ Padova INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy.
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- Nowotny, W. (författare)
- Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
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- Grellmann, R. (författare)
- Univ Cologne, Phys Inst, Zulpicher Str 77, D-50397 Cologne, Germany.
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Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria Univ Libre Bruxelles, Inst Astron & Astrophys, Blvd Triomphe CP 226, B-1050 Brussels, Belgium. (creator_code:org_t)
- 2017-04-06
- 2017
- Engelska.
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Ingår i: Astronomy and Astrophysics. - : EDP SCIENCES S A. - 0004-6361 .- 1432-0746. ; 600
- Relaterad länk:
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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
Ämnesord
Stäng
- Context. Modeling stellar atmospheres is a complex and intriguing task in modern astronomy. A systematic comparison of models with multi-technique observations is the only efficient way to constrain the models. Aims. We intend to perform self-consistent modeling of the atmospheres of six carbon-rich AGB stars (R Lep, R Vol, Y Pav, AQ Sgr, U Hya, and X TrA) with the aim of enlarging the knowledge of the dynamic processes occurring in their atmospheres. Methods. We used VLTI/MIDI interferometric observations, in combination with spectro-photometric data, and compared them with self-consistent, dynamic model atmospheres. Results. We found that the models can reproduce spectral energy distribution (SED) data well at wavelengths longer than 1 mu m, and the interferometric observations between 8 mu m and 10 mu m. Discrepancies observed at wavelengths shorter than 1 mu m in the SED, and longer than 10 mu m in the visibilities, could be due to a combination of data- and model-related effects. The models best fitting the Miras are significantly extended, and have a prominent shell-like structure. On the contrary, the models best fitting the non-Miras are more compact, showing lower average mass loss. The mass loss is of episodic or multi-periodic nature but causes the visual amplitudes to be notably larger than the observed ones. A number of stellar parameters were derived from the model fitting: T-Ross, L-Ross, M, C/O, and. M. Our findings agree well with literature values within the uncertainties. TRoss, and LRoss are also in good agreement with the temperature derived from the angular diameter T(theta((V-K))) and the bolometric luminosity from the SED fitting L-bol, except for AQ Sgr. The possible reasons are discussed in the text. Finally, theta(Ross) and theta((V-K)) agree with one another better for the Miras than for the non-Miras targets, which is probably connected to the episodic nature of the latter models. We also located the stars in the H-R diagram, comparing them with evolutionary tracks. We found that the main derived properties (L, T-eff, C/O ratios and stellar masses) from the model fitting are in good agreement with TP-AGB evolutionary calculations for carbon stars carried out with the COLIBRI code.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- stars: AGB and post-AGB
- stars: atmospheres
- stars: mass-loss
- stars: carbon
- techniques: interferometric
- techniques: high angular resolution
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