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Published September 20, 2009 | Published
Journal Article Open

First L-Band Interferometric Observations of a Young Stellar Object: Probing the Circumstellar Environment of MWC 419


We present spatially resolved K- and L-band spectra (at spectral resolution R = 230 and R = 60, respectively) of MWC 419, a Herbig Ae/Be star. The data were obtained simultaneously with a new configuration of the 85 m baseline Keck Interferometer. Our observations are sensitive to the radial distribution of temperature in the inner region of the disk of MWC 419. We fit the visibility data with both simple geometric and more physical disk models. The geometric models (uniform disk and Gaussian) show that the apparent size increases linearly with wavelength in the 2-4 μm wavelength region, suggesting that the disk is extended with a temperature gradient. A model having a power-law temperature gradient with radius simultaneously fits our interferometric measurements and the spectral energy distribution data from the literature. The slope of the power law is close to that expected from an optically thick disk. Our spectrally dispersed interferometric measurements include the Br γ emission line. The measured disk size at and around Br γ suggests that emitting hydrogen gas is located inside (or within the inner regions) of the dust disk.

Additional Information

© 2009 American Astronomical Society. Print publication: Issue 1 (2009 September 20); received 2009 April 9, accepted for publication 2009 July 20; published 2009 August 25. Keck Interferometer is funded by the National Aeronautics and Space Administration (NASA). Observations presented were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. We thank E. Appleby, B. Berkey, A. Booth, A. Cooper, S. Crawford, W. Dahl, C. Felizardo, J. Garcia-Gathright, J. Herstein, R. Ligon, D. Medeiros, D. Morrison, T. Panteleeva, B. Parvin, B. Smith, K. Summers, K. Tsubota, C. Tyau, and E. Wetherell for their contributions to the instrument development, integration, and operations. S. Ragland also thanks M. Hrynevych, M. Kassis, and J. Woillez for useful discussions. We thank the referee for constructive critical comments that helped us to significantly improve the paper.

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