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Session 47 - Circumstellar Disks & Shells.
Display session, Thursday, January 08
Over the past decade, optical observations have obtained increasingly finer detail about the dust disk around the star, \beta Pictoris. These observations have led most astronomers to conclude that the \beta Pic system is a proto-planetary system or system where one or more planets have already formed.
In this paper, we present new observations made by the Space Telescope Imaging Spectrograph (STIS), which was installed on the Hubble Space Telescope in February 1997. With its high resolution (0\farcs1), stable point spread function, occulting mask and Lyot stop, this instrument becomes a powerful coronograph. In September 1997, we used STIS to observe the \beta Pic system at three telescope roll angles. Since the PSF does not rotate as the roll angle is changed, the disk can be separated after the fact from the stellar PSF. For one set of observations, the star was placed behind an occulting wedge 1" across; for the other set, a wedge 2" across.
The reduced images show the disk as close in to the star as 13 AU. The ``warp'' in the disk, previously noted in WFPC2 data and ground-based observations, is clearly visible. We compare the observed properties of the warp to theoretical predictions in order to assess whether the warp is caused by gravitational perturbation by a planet or is a radiation-induced warp.
Program listing for Thursday