THE BETA-PICTORIS PHENOMENON IN A-SHELL STARS - DETECTION OF ACCRETING GAS

We present the results of an expanded survey of A-shell stars using IU E high-dispersion spectra and find accreting, circumstellar gas in the line of sight to nine stars, in addition to the previously identified beta Pie, HR 10, and 131 Tau, which can be followed to between +70 an d 100 km s(-1) relative to the star. Two of the program stars, HD 8819 5 and HD 148283, show variable high-velocity gas. Given the small numb er of IUE spectra for our program stars, detection of high-velocity, a ccreting gas in 2/3 of the A-shell stars sampled indicates that accret ion is an intrinsic part of the A-shell phenomenon and that beta Pic i s not unique among main-sequence A stars in exhibiting such activity. Our program stars, as a group, have smaller column densities of high-v elocity gas and smaller near-IR excesses compared with beta Pie. These features are consistent with greater central clearing of a remnant de bris disk, compared with beta Pie, and suggest that the majority of fi eld A-shell stars are older than beta Pie.