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J.E. Neff (College of Charleston), K.P. Cheng (Cal State U. Fullerton)
We have used infrared, visual, and ultraviolet observations to study the circumstellar environments of all nearby A stars. We have been looking for stars with circumstellar dust disks and/or gas infall/outflow similar to that seen around the proto-planetary system candidate \beta Pictoris. Among the 62 A stars in our survey, the most interesting object so far is 2 Andromedae (HD 217782). Our ultraviolet spectra revealed the existence of circumstellar as well as interstellar gas along this line-of-sight (d=107.2 pc; l=102.5o). We also detected variable, redshifted Ca II K absorption features in our ground-based visual spectra. These variable circumstellar Ca II absorption features and the presence of Al III and Fe II circumstellar absorption lines in our HST/GHRS spectra of 2 And are similar to those observed in the \beta Pictoris. However, unlike \beta Pic, 2 And has no detectable infrared excess in our IRAS dust survey of nearby A stars. In order to better constrain the characteristics and origin of the circumstellar gas, we observed 2 And with FUSE for 20 kiloseconds on 3 and 4 July 2001. Our FUSE spectrum shows a well-exposed continuum longward of 1100 Å\ with a wealth of photospheric, interstellar, and circumstellar absorption lines. We did not detect any broad, strong stellar Al III or O VI emission lines like those seen in the FUSE spectrum of \beta Pic.
This work is supported by NASA grant NAG5-10313 to the College of Charleston and NASA grant NAG5-10312 and NSF grant AST-9819737 to California State University/Fullerton.
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The author(s) of this abstract have provided an email address for comments about the abstract: neffj@cofc.edu