Ragland, S. and Traub, W. A. and Berger, J.P. and Danchi, W. C. and Monnier, J. D. and Willson, L. A. and Carleton, N. P. and Lacasse, M. G. and Millan-Gabet, R. and Pedretti, E. and Schloerb, F. P. and Cotton, W. D. and Townes, C. H. and Brewer, M. and Haguenauer, P. and Kern, P. and Labeye, P. and Malbet, F. and Malin, D. and Pearlman, M. and Perraut, K. and Souccar, K. and Wallace, G. (2006) First surface-resolved results with the infrared optical telescope array imaging interferometer: Detection of asymmetries in asymptotic giant branch stars. Astrophysical Journal, 652 (1). pp. 650-660. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:RAGapj06
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We have measured nonzero closure phases for about 29% of our sample of 56 nearby asymptotic giant branch (AGB) stars, using the three-telescope Infrared Optical Telescope Array (IOTA) interferometer at near-infrared wavelengths (H band) and with angular resolutions in the range 5–10 mas. These nonzero closure phases can only be generated by asymmetric brightness distributions of the target stars or their surroundings. We discuss how these results were obtained and how they might be interpreted in terms of structures on or near the target stars. We also report measured angular sizes and hypothesize that most Mira stars would show detectable asymmetry if observed with adequate angular resolution.
|Additional Information:||© 2006 The American Astronomical Society. Received 2004 June 28; accepted 2006 June 20. This work was performed in part under contract with the Jet Propulsion Laboratory (JPL) through a Michelson Postdoctoral Fellowship to S. Ragland, funded by NASA as an element of the Navigator (planet finder) Program. JPL is managed for NASA by the California Institute of Technology. We acknowledge support from the NSF through research grants AST 01-38303 and AST 04-56047. The IOTA is principally supported by the Smithsonian Astrophysical Observatory and the University of Massachusetts. The National Radio Astronomy Observatory (NRAO) is operated by Associated Universities, Inc., under cooperative agreement with the NSF. We thank the referee for constructively critical comments that have helped us to significantly improve the paper. This research has made use of NASA's Astrophysics Data System Bibliographic Services and AAVSO's database for light curves.|
|Subject Keywords:||circumstellar matter—stars: AGB and post-AGB—stars: imaging—stars: spots—surveys—techniques: interferometric|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Lindsay Cleary|
|Deposited On:||22 Feb 2007|
|Last Modified:||26 Dec 2012 09:32|
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