Molecular Gas in the Inner 1 AU of the TW Hya and GM Aur Transitional Disks
Abstract
We report the detection of CO rovibrational emission from the transitional disks around the T Tauri stars TW Hya and GM Aur. Transitional disks are characterized by significant mid- to far-infrared (IR) dust emission combined with a relative deficit in the near-IR, indicating the presence of an optically thick outer disk but a reduced surface density of small dust grains in the inner disk. Kinematic fits to the resolved CO emission lines demonstrate that they arise from within the tenuous inner disk. Excitation diagram analyses yield rotational temperatures also consistent with small emission radii as well as densities implying dynamically significant amounts of gas in the inner disk and a gas-to-small dust grain ratio in excess of that in dense clouds. Nevertheless, gas densities are not high enough to maintain current accretion rates for more than a few hundred years without replenishment, and transfer of gas from the outer to inner disk is therefore likely required.
Additional Information
© 2007 The American Astronomical Society. Received 2006 June 6; accepted 2006 December 20; published 2007 January 16. The authors thank Ken Hinkle for his assistance with the Phoenix observations. We also acknowledge support from the NASA Spitzer and Origins programs. Data presented herein 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. This work also utilized the Gemini Observatory as part of program GS-2006A-C-10. Gemini is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership.Attached Files
Published - SALapjl07.pdf
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- CaltechAUTHORS:20100113-082939196
- NASA
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2010-01-19Created from EPrint's datestamp field
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2021-11-08Created from EPrint's last_modified field
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- Division of Geological and Planetary Sciences