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Tracing a decade of...
Tracing a decade of activity towards a yellow hypergiant. The spectral and spatial morphology of IRC+10420 at au scales
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- Koumpia, Evgenia (författare)
- University of Leeds
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- Oudmaijer, R. D. (författare)
- University of Leeds
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De Wit, W-J (författare)
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- Merand, A. (författare)
- European Southern Observatory (ESO)
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- Black, John H, 1949 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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Ababakr, K. M. (författare)
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(creator_code:org_t)
- 2022-07-23
- 2022
- Engelska.
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 515:2, s. 2766-2777
- Relaterad länk:
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https://research.cha...
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https://doi.org/10.1...
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Abstract
Ämnesord
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- The fate of a massive star during the latest stages of its evolution is highly dependent on its mass-loss history and geometry, with the yellow hypergiants (YHGs) being key objects. We present near-IR interferometric observations of the famous YHG IRC+10420 and blue spectra taken between 1994 and 2019. Our 2.2-mu m GRAVITY/VLTI observations attain a spatial resolution of similar to 5 stellar radii and spatially resolve the hot emission in the K-band tracing the gas via Na i doublet emission and the Br gamma emission. Our geometric modelling reveals a compact neutral zone (Na i) which is slightly larger than the continuum but within an extended Br gamma emitting region. Our study confirms an hour-glass geometry of the wind, but we find no signature of a companion at 7-800 au separations at the contrast limit of our observations (3.7 mag at 3 sigma) to explain this geometry. We report an evolution of the ejecta over 7 yr, and constrain the opening angle of the hour-glass to be <10 degrees. Lastly, we present the first blue optical spectra of IRC+10420 since 1994. The multi-epoch data indicate that the spectral type, and thus temperature, of the object has essentially remained constant during the intervening years. Therefore, the observed increase in temperature of 2000 K in less than two decades prior to 1994 is now halted. This suggests that this YHG has 'hit' the White Wall in the HR-diagram preventing it from evolving blue-wards, and will likely undergo a major mass-loss event in the near future.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Meteorologi och atmosfärforskning (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Meteorology and Atmospheric Sciences (hsv//eng)
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
- NATURVETENSKAP -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)
Nyckelord
- techniques: interferometric
- stars: mass-loss
- stars: evolution
- stars: individual: IRC+10420
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