Title: The limb-darkened Arcturus: imaging with the IOTA/IONIC interferometer
Authors: Lacour, S ×
Meimon, S
Thiebaut, E
Perrin, G
Verhoelst, Tijl
Pedretti, E
Schuller, P. A
Mugnier, L
Monnier, J
Berger, J. P
Haubois, X
Poncelet, A
Le Besnerais, G
Eriksson, K
Millan-Gabet, R
Ragland, S
Lacasse, M
Traub, W #
Issue Date: Jul-2008
Publisher: Edp sciences s a
Series Title: Astronomy & astrophysics vol:485 issue:2 pages:561-570
Abstract: Aims. We undertook an H band interferometric examination of Arcturus, a star frequently used as a spatial and spectral calibrator. Methods: Using the IOTA 3 telescope interferometer, we performed spectro-interferometric observations (R≈35) of Arcturus. Atmospheric models and prescriptions were fitted to the data to derive the brightness distribution of the photosphere. Image reconstruction was performed using two software algorithms: Wisard and Mira. Results: An achromatic power law proved to be a good model of the brightness distribution, with a limb darkening compatible with the one derived from atmospheric model simulations using our marcs model. A Rosseland diameter of 21.05±0.21 was derived, corresponding to an effective temperature of Teff = 4295±26 K. No companion was detected from the closure phases, with an upper limit on the brightness ratio of 8×10-4 at 1 AU. The dynamic range at such distance from the photosphere was established as 1.5×10-4 (1σ rms). An upper limit of 1.7×10-3 was also derived for the level of brightness asymmetries present in the photosphere.
ISSN: 0004-6361
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Institute of Astronomy
× corresponding author
# (joint) last author

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