AAS 201st Meeting, January, 2003
Session 49. Eta Carinae, LBVs, and Circumstellar Disks
Poster, Tuesday, January 7, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[49.16] Far-Ultraviolet Observations of the Circumstellar Gas in the 2 Andromedae System

K.-P. Cheng (California State University, Fullerton), J.E. Neff (College of Charleston)

The A5 star \beta~Pictoris is a possible young planetary system with the best-studied circumstellar disk. Our visible and ultraviolet observations of 2~Andromedae indicated that this A3 star has ``\beta~Pictoris-like'' gas infall. We present the far-ultraviolet spectrum (905 -- 1195 Å)\ of 2~And we obtained with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer (FUSE). Unlike \beta~Pic, 2~And's FUSE spectum does not show strong chromospheric emission lines from \ion{C}{3} and \ion{O}{6}. However, 2~And's FUSE spectrum contains many non-photospheric lines that allow us to probe the circumstellar gas. For example, between 1120 and 1140 Å,\ we detected several \ion{Fe}{3} absorption lines arising from hyper-fine levels of ground state, which cannot arise in the interstellar medium and can be used as diagnostics of the circumstellar gas. We also detected circumstellar \ion{Fe}{2}, \ion{Cr}{3}, and \ion{Mn}{3} lines that are sufficiently strong to allow circumstellar gas velocity determinations.

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© 2002. The American Astronomical Soceity.