The dusty AGB star RS CrB: first mid-infrared interferometric observations with the Keck Telescopes
| Autor: | B. Mennesson, C. Koresko, M. J. Creech-Eakman, E. Serabyn, M. M. Colavita, R. Akeson, E. Appleby, J. Bell, A. Booth, S. Crawford, W. Dahl, J. Fanson, C. Felizardo, J. Garcia, J. Gathright, J. Herstein, E. Hovland, M. Hrynevych, E. Johansson, D. Le Mignant, R. Ligon, R. Millan-Gabet, J. Moore, C. Neyman, D. Palmer, T. Panteleeva, C. Paine, S. Ragland, L. Reder, A. Rudeen, T. Saloga, M. Shao, R. Smythe, K. Summers, M. Swain, K. Tsubota, C. Tyau, G. Vasisht, P. Wizinowich, J. Woillez |
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| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: |
Physics
Photosphere Spectrometer Opacity Red giant Astrophysics (astro-ph) FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Spectral line Wavelength Space and Planetary Science Asymptotic giant branch Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Variable star Astrophysics::Galaxy Astrophysics |
| Popis: | We report interferometric observations of the semi-regular variable star RS CrB, a red giant with strong silicate emission features. The data were among the first long baseline mid-infrared stellar fringes obtained between the Keck telescopes, using parts of the new nulling beam combiner. The light was dispersed by a low-resolution spectrometer, allowing simultaneous measurement of the source visibility and intensity spectra from 8 to 12 microns. The interferometric observations allow a non-ambiguous determination of the dust shell spatial scale and relative flux contribution. Using a simple spherically-symmetric model, in which a geometrically thin shell surrounds the stellar photosphere, we find that ~30% to ~70% of the overall mid-infrared flux - depending on the wavelength - originates from 7-8 stellar radii. The derived shell opacity profile shows a broad peak around 11 microns (tau ~ 0.06), characteristic of Mg-rich silicate dust particles. Accepted for publication in ApJ Letters |
| Databáze: | OpenAIRE |
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