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          Institute: MPI für Radioastronomie     Collection: Publikationen des MPI für Radioastronomie     Display Documents



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ID: 125410.0, MPI für Radioastronomie / Publikationen des MPI für Radioastronomie
JHK '-band IOTA interferometry of the circumstellar environment of R CrB
Authors:Ohnaka, K.; Beckmann, U.; Berger, J. P.; Brewer, M. K.; Hofmann, K. H.; Lacasse, M. G.; Malanushenko, V.; Millan-Gabet, R.; Monnier, J. D.; Pedretti, E.; Schertl, D.; Schloerb, F. P.; Shenavrin, V. I.; Traub, W. A.; Weigelt, G.; Yudin, B. F.
Language:English
Date of Publication (YYYY-MM-DD):2003-09
Title of Journal:Astronomy & Astrophysics
Journal Abbrev.:Astron. Astrophys.
Volume:408
Issue / Number:2
Start Page:553
End Page:558
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:We report the first long-baseline interferometry of the circumstellar dust environment of R CrB. The observations were carried out with the Infrared Optical Telescope Array (IOTA), using our new JHK' beam combiner which enables us to record fringes in the J, H, and K' bands simultaneously. The circumstellar dust envelope of R CrB is resolved at a baseline of 21 m along a position angle of similar to170degrees, and the visibilities in the J, H, and K' bands are 0.97 +/- 0.06, 0.78 +/- 0.06, and 0.61 +/- 0.03, respectively. These observed visibilities, together with the K'-band visibility obtained by speckle interferometry with baselines of up to 6 m, and the spectral energy distribution are compared with predictions from spherical dust shell models which consist of the central star and an optically thin dust shell. The comparison reveals that the observed J- and H-band visibilities are in agreement with those predicted by these models, and the inner radius and inner boundary temperature of the dust shell were derived to be 60-80 R-* and 950-1050 K, respectively. However, the predicted K'-band visibilities are found to be similar to10% smaller than the one obtained with IOTA. Given the simplifications adopted in our models and the complex nature of the object, this can nevertheless be regarded as rough agreement. As a hypothesis to explain this small discrepancy, we propose that there might be a group of newly formed dust clouds, which may appear as a third visibility component.
Free Keywords:techniques : interferometric, stars : circumstellar matter, stars : mass-loss, stars : individual : R CrB, stars :, variable : general, infrared : stars
Comment of the Author/Creator:Date: 2003, SEP
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Radioastronomie
External Affiliations:Max Planck Inst Radioastron, D-53121 Bonn, Germany.; Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA.; Observ Grenoble, Astrophys Lab, F-38041 Grenoble, France.; Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA.; Crimean Astrophys Observ, UA-98409 Crimea, Ukraine.; CALTECH, Pasadena, CA 91125 USA.; Univ Michigan, Ann Arbor, MI 48109 USA.; Sternberg Astron Inst, Moscow 119899, Russia.
Identifiers:ISI:000185006700014 [ID No:1]
ISSN:0004-6361 [ID No:2]
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