The limb-darkened Arcturus: imaging with the IOTA/IONIC interferometer - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2008

The limb-darkened Arcturus: imaging with the IOTA/IONIC interferometer

S. Lacour
S. Meimon
  • Fonction : Auteur
Éric Thiébaut
G. Perrin
T. Verhoelst
  • Fonction : Auteur
E. Pedretti
  • Fonction : Auteur
P. A. Schuller
  • Fonction : Auteur
L. Mugnier
  • Fonction : Auteur
J. Monnier
X. Haubois
  • Fonction : Auteur
A. Poncelet
  • Fonction : Auteur
G. Le Besnerais
  • Fonction : Auteur
K. Eriksson
  • Fonction : Auteur
R. Millan-Gabet
  • Fonction : Auteur
S. Ragland
  • Fonction : Auteur
M. Lacasse
  • Fonction : Auteur
W. Traub
  • Fonction : Auteur

Résumé

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.

Dates et versions

hal-00398519 , version 1 (24-06-2009)

Identifiants

Citer

S. Lacour, S. Meimon, Éric Thiébaut, G. Perrin, T. Verhoelst, et al.. The limb-darkened Arcturus: imaging with the IOTA/IONIC interferometer. Astronomy and Astrophysics - A&A, 2008, 485, pp.561. ⟨10.1051/0004-6361:200809611⟩. ⟨hal-00398519⟩
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