AN INTERFEROMETRIC STUDY OF THE FOMALHAUT INNER DEBRIS DISK. I. NEAR-INFRARED DETECTION OF HOT DUST WITH VLTI/VINCI
- Dept. d'Astrophysique, Geophysique and Oceanographie Universite de Liege, 17 Allee du Six Aout, B-4000 Sart Tilman (Belgium)
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
- European Southern Observatory, Casilla 19001, Santiago 19 (Chile)
- LESIA-UMR 8109, CNRS and Observatoire de Paris-Meudon, 5 place J. Janssen, F-92195 Meudon (France)
- LAOG-UMR 5571, CNRS and Universite Joseph Fourier, BP 53, F-38041 Grenoble (France)
The innermost parts of dusty debris disks around main-sequence stars are currently poorly known due to the high contrast and small angular separation with their parent stars. Using near-infrared interferometry, we aim to detect the signature of hot dust around the nearby A4 V star Fomalhaut, which has already been suggested to harbor a warm dust population in addition to a cold dust ring located at about 140 AU. Archival data obtained with the VINCI instrument at the VLTI are used to study the fringe visibility of the Fomalhaut system at projected baseline lengths ranging from 4 m to 140 m in the K band. A significant visibility deficit is observed at short baselines with respect to the expected visibility of the sole stellar photosphere. This is interpreted as the signature of resolved circumstellar emission, producing a relative flux of 0.88% +- 0.12% with respect to the stellar photosphere. While our interferometric data cannot directly constrain the morphology of the excess emission source, complementary data from the literature allow us to discard an off-axis point-like object as the source of circumstellar emission. We argue that the thermal emission from hot dusty grains located within 6 AU from Fomalhaut is the most plausible explanation for the detected excess. Our study also provides a revised limb-darkened diameter for Fomalhaut (theta{sub LD} = 2.223 +- 0.022 mas), taking into account the effect of the resolved circumstellar emission.
- OSTI ID:
- 21367464
- Journal Information:
- Astrophysical Journal, Vol. 704, Issue 1; Other Information: DOI: 10.1088/0004-637X/704/1/150; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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