Skip to main content
Other
High-resolution Imaging of Dust Shells Using Keck aperture Masking and the IOTA Interferometer
Astronomy Department Faculty Publication Series
  • J. D. Monnier, University of Michigan - Ann Arbor
  • R. Millan-Gabet, California Institute of Technology
  • P. G. Tuthill, University of Sydney
  • W. A. Traub, Harvard-Smithsonian Center for Astrophysics
  • V. Coudé du Foresto, Observatoire de Paris-Meudon
  • W. C. Danchi, NASA Goddard Space Flight Center
  • M. G. Lacasse, Harvard-Smithsonian Center for Astrophysics
  • S. Morel, European Southern Observatory
  • G. Perrin, Observatoire de Paris-Meudon
  • I. L. Porro, Massachusetts Institute of Technology
  • F. P. Schloerb, University of Massachusetts - Amherst
  • C. H. Townes, University of California - Berkeley
Publication Date
2004
Abstract

We present first results of an experiment to combine data from Keck aperture masking and the Infrared-Optical Telescope Array (IOTA) to image the circumstellar environments of evolved stars with ∼20 milliarcsecond resolution. The unique combination of excellent Fourier coverage at short baselines and highquality long-baseline fringe data allows us to determine the location and clumpiness of the inner-most hot dust in the envelopes, and to measure the diameters of the underlying stars themselves. We find evidence for large-scale inhomogeneities in some dust shells and also significant deviations from uniform brightness for the photospheres of the most evolved M-stars. Deviations from spherically-symmetric mass loss in the red supergiant NML Cyg could be related to recent evidence for dynamically-important magnetic fields and/or stellar rotation. We point out that dust shell asymmetries, like those observed here, can qualitatively explain the difficulty recent workers have had in simultaneously fitting the broad-band spectral energy distributions and high-resolution spatial information, without invoking unusual dust properties or multiple distinct shells (from hypothetical “superwinds”). This paper is the first to combine optical interferometry data from multiple facilities for imaging, and we discuss the challenges and potential for the future of this method, given current calibration and software limitations.

Comments
This paper was harvested from ArXiv.org and ArXiv identifier is arXiv:0401363v1
DOI
https://doi.org/10.1086/382218
Pages
436-461
Citation Information
J. D. Monnier, R. Millan-Gabet, P. G. Tuthill, W. A. Traub, et al.. "High-resolution Imaging of Dust Shells Using Keck aperture Masking and the IOTA Interferometer" Vol. 605 (2004)
Available at: http://works.bepress.com/f_schloerb/1/