The limb-darkened Arcturus: imaging with the IOTA/IONIC interferometer
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 (1σrms). An upper limit of 1.7×10^−3 was also derived for the level of brightness asymmetries present in the photosphere.
Additional Information
© ESO 2008. Received 19 February 2008 / Accepted 31 March 2008. S.L. acknowledges financial support through a Lavoisier fellowship. This work also received the support of PHASE, the high angular resolution partnership between ONERA, Observatoire de Paris, CNRS and University Denis Diderot Paris 7.Attached Files
Published - LACaanda08.pdf
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Additional details
- Eprint ID
- 13841
- Resolver ID
- CaltechAUTHORS:LACaanda08
- Lavoisier Fellowship
- PHASE
- Created
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2009-04-03Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field