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S. Brittain, T. Rettig (University of Notre Dame), T. Simon (University of Hawaii), C. Kulesa (University of Arizona), M. DiSanti (Goddard Space Flight Center)
We present a comparison of CO infrared emission from the inner circumstellar disks around the Herbig AeBe stars AB Aurigae and HD 141569. The CO emission from the disk of the 2-4 Myr star AB Aurigae shows at least two temperature components, the inner rim (1500K) and the outer flared disk (160K). For both components, the excitation of CO is dominated by infrared radiation. For the more evolved 5-10 Myr HAeBe star HD 141569, the relative intensity of the CO emission lines are consistent with a rotational temperature of 190±30K. In this case, both infrared and UV fluorescence mechanisms are effective in the excitation of CO. The column density of the gas is 9.0 x1011 cm-2 indicating1019g of CO. The observations indicate the inner disk has been cleared of CO gas by stellar radiation out to a minimum of ~17 AU. The residual mass of CO suggests the inner disk of HD 141569 is not in an active phase of planet building but it does not rule out the possibility that giant planet building has previously occurred.
This work is supported by the Astronomy Division of the National Science Foundation
The author(s) of this abstract have provided an email address for comments about the abstract: sbrittai@nd.edu
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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.