AAS Meeting #193 - Austin, Texas, January 1999
Session 69. Circumstellar Material
Display, Friday, January 8, 1999, 9:20am-6:30pm, Exhibit Hall 1

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[69.05] Beta Pictoris-like Ca II Circumstellar Gas Around Four Nearby A Stars

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

The main sequence A star Beta Pictoris has been known as a planetary system candidate for more than a decade. It has been suggested that the short-term variations of circumstellar gas absorption components in the Beta Pic system could be due to the evaporation of comet-size bodies. It also has been suggested that the huge dust disk around Beta Pic could be an analog of our Kuiper Belt.

We present the results of our search for Beta Pictoris-like systems in a volume-limited sample of 62 nearby A stars. Our survey included two independent studies: one of the circumstellar dust using IRAS data, and the other of the circumstellar gas using high-resolution and high signal-to-noise visual and ultraviolet spectra. We found that more than 18 dust, and more than a dozen stars have circumstellar gas. Our further monitoring of the Ca II K and Na I D lines has revealed that at least 4 of these stars have Beta Pic-like variable spectral signatures indicating gaseous infall. Our findings will help us to understand the inter-relationship between circumstellar gas and dust.

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