AAS 198th Meeting, June 2001
Session 51. Optical Interferometry
Topical Session Oral, Wednesday, June 6, 2001, 8:30am-12:30pm, 2:30-6:00pm, C106

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[51.17] Images of massive young stars MWC 349A and LkHalpha 101

P. G. Tuthill (School of Physics, Sydney University, NSW 2006, Australia.), J. D. Monnier (Harvard-Smithsonian Center for Astrophysics), W. C. Danchi (NASA Goddard Space Flight Center)

We have obtained full images of two of the brightest young stellar objects in the near infrared using aperture masking interferometry on the Keck 1 telescope. Herbig Ae/Be star LkHalpha 101 shows a face-on circular disk with a central cavity, while MWC 349A shows an elongated appearance (axial ratio about 2:1) with a major axis at a position angle of 100 deg. Both objects are believed to be intermediate/high mass counterparts of the T Tauris, and the startling differences in apparent morphology between them we attribute to viewing angle. In the case of MWC 349A we have an almost edge-on view of an accretion disk, while LkHalpha 101 is consistent with a more polar viewing angle. Significantly, the latter disk is not exactly in the plane of the sky, but is tilted away from the line of sight to the southwest (by <35 deg). This allows a clear view across the central cavity to the hottest inner regions of the disk in direct contact with the stellar radiation field. Taken together, the high resolution images of these two stars constitute the first infrared pictures of hot disks at such early epochs. They are in accord with the broad scenario of stellar formation through disk accretion processes, however on closer examination discrepancies with classical models are encountered. In particular, the size scale of the inner cavity of the LkHalpha 101 disk is larger than expected, and we suggest that this radius is set by dust grain sublimation by the radiant stellar field. Images at such high angular scales combined with numerical radiative transfer modelling promise to deliver concrete physical models of these very young stellar systems in the near future.

If you would like more information about this abstract, please follow the link to http://www.physics.usyd.edu.au/~gekko/gekko.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: gekko@ssl.berkeley.edu

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