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| Paper: |
FUSE Observations of Main-sequence A-type Stars' Circumstellar Gas |
| Volume: |
348, Astrophysics in the Far Ultraviolet: Five Years of Discovery with FUSE |
| Page: |
300 |
| Authors: |
Cheng, K.-P.; Neff, J.E. |
| Abstract: |
Since the discovery of Vega's (A0 V) large thermal IR excess over the extrapolated stellar photospheric radiation, dust disks around a large fraction of main-sequence A-type stars have been found by IRAS and ISO. Subsequent visual and ultraviolet observations of two of these stars, Beta Pic (A5 V) and 51 Oph (A0 V), have revealed a dynamic circumstellar gas disk. Although the amount of gas around main sequence A-type stars is much less than around T Tauri stars, circumstellar gas plays a crucial role in planet system formation. Many circumstellar absorption lines in the far-ultraviolet wavelength range are excellent diagnostics of circumstellar gas properties. We have obtained and analyzed FUSE spectra of two main-sequence A-type stars (2 And and δ UMa) to study the origin of their circumstellar gas disks and the possible link between their circumstellar gas and dust. |
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