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Session 113 - Observations of the Circumstellar Environment of YSOs.
Oral session, Thursday, January 18
Corte Real, Hilton
We present Hubble Space Telescope Planetary Camera images and new ^13CO 2-1 OVRO millimeter interferometery of the pre-main sequence star GM Aurigae. The HST images reveal a flattened circumstellar reflection nebula extending symmetrically from the star to radial distances of 3^\prime\prime (450 AU) along position angle 60^\circ. The nebula is seen in PSF-subtracted images made in three different broadband filters and has an axial ratio \approx4:1. The new ^13CO line map further resolves the flattened molecular gas structure first seen by Koerner et al. 1993; the size, aspect ratio, and orientation of this molecular bar are comparable to those of the optical nebula. These results strongly support an interpretation of the reflection nebulosity as an illuminated outer surface of the molecular gas disk surrounding GM Aurigae. Comparison of the observed nebula with single scattering models suggests that the disk is viewed at a latitude \approx 30^\circ above its equator plane.
Program listing for Thursday