Spatial Resolution of the Silicate Feature in T Tauri Binary Stars

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Session 44 -- Young Stars, T Tauri Stars, Herbig Haro Objects
Display presentation, Wednesday, 1, 1994, 9:20-6:30

[44.05] Spatial Resolution of the Silicate Feature in T Tauri Binary Stars

J. E. Van Cleve, T. L. Hayward, J. R. Houck (Cornell University), J. Miles (National Air and Space Museum)

We took low resolution spectra from 7.9 to 13.0 $\mu$m of the T Tauri binary systems T Tau and Haro 6-10, as well as images of these systems and UY Aur, FV Tau, and FX Tau at 7.9 or 8.8, 10.3, and 12.5 $\mu$m, using the Cornell SpectroCam-10 imaging spectrometer on the 5-m Hale telescope. These binaries resemble planetary systems in that the projected separation of the components (100 to 180 AU) is roughly the diameter of our Solar System. For the images, the observed flux distribution along the axis of the binary was deconvolved by the flux distribution perpendicular to that axis. The resulting visibility function was then fitted to a two point-source model to obtain the relative flux of the components. The spectra were deconvolved by calibrator star spectra, and the model was fit to each wavelength of the visibility function spectrum to obtain the relative flux. Images and spectra agree and show that in binaries which contain an infrared companion -- such as T Tau and Haro 6-10 -- the IR companion has a deep silicate absorption feature, while the other component is featureless or shows a weak emission feature. In Haro 6-10, for example, the optical depth of the silicate absorption in the IR companion (Haro 6-10 N) is $\approx 1$ near its maximum at 9.7 $\mu$m. These results suggest that the components (including dust shells or disks around each star) of an IR companion system are not both coplanar and coeval. For a giant planet and a single star, however, we'd expect a circumplanetary disk to lie in the plane of the circumstellar disk, and be about the same age. At least for the IR companion systems, the analogy of binary stars and planetary systems is not a good one in this respect.

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