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A.J. Weinberger (UCLA), G. Schneider (U. Arizona), E.E. Becklin (UCLA), B.A. Smith (U. Hawaii), D.C. Hines (U. Arizona)
We present the first near infrared imaging of a circumstellar disk around the classical T-Tauri star TW Hya. This young, approximately 10 Myr old, K7 star is the archetypal member of an isolated association of stars (Webb et al., 1999, ApJ, 512, L67) thought to be the site of recent star-formation closest to the Earth.
Point spread function subtracted NICMOS camera 2 coronagraphic images of TW Hya at 1.1 and 1.6 microns (F110W and F160W filters) from two epochs are presented. Both reveal a face-on disk seen in reflected light extending to a radial distance of 3 arcseconds (approximately 150 parsecs). In both bands, the surface brightness of the disk, in these high S/N observations, falls off approximately as r ^ -3. We present the details of the observations and photometry of the system and discuss in detail the nature of the disk.
These observations of TW Hya are part of the NICMOS Instrument Definition Team's Environments of Nearby Stars program. Other members of the TW Hya assocation were also surveyed for the presence of disks (eg., HR 4796A ; Schneider, et. al, ApJL, 513, L128, and HD 98800; Low, et al., 1999, elsewhere at this meeting) and substellar companions (eg., CD -33.7795; Lowrance, et al., 1999, ApL, 512, L68).
This work is supported by NASA grant NAG 5-3042. This paper is based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS5-26555.
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