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

K.-P. Cheng, James E. Neff
2003 Astronomical Journal  
The A5 star p Pictoris is a possible young planetary system and has the best-studied circumstellar disk. Our visible and iiltraviolet observatinns of 2 Andromed?e indicated that this A3 star has p Pictoris-like gas infall. 'Wcptesmz the far-ultraviolet spectrum (905-1 195 A) of 2 And we obtained with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer (FUSE). Unlike p Pic, 2 And's FUSE spectrum does not show strong chromospheric emission lines from C 111 and 0 VI. However, 2 And's FUSE
more » ... r, 2 And's FUSE spectrum contains manyenonphotospheric lines that allow us to probe the circumstellar gas. For example, between 1120 and 1140 A, we detected several Fe 111 absorption lines arising from hyperfine levels of ground state, which cannot be formed in the interstellar medium. These lines are good diagnostics of the circumstellar gas. We also detected circumstellar Fe 11, Cr 1x1, Mn 111, and 0 I (ID) lines. The simultaneous presence of these species suggests that the circumstellar environment of 2 And could include regions with different temperatures and densities.
doi:10.1086/345795 fatcat:odtfndvri5hhtkluq5pwjk26oy