We have undertaken a spectroscopic survey at high dispersion of some known Bootis stars with a view to testing the hypothesis of Venn & Lambert (1990), who suggested a depleted gas accretion model. In a first paper we found (Hauck et al. 1995, hereafter Paper I) circumstellar shell (CS) features in the CaII-K line of two stars (HD 16955 and HD 204965) and a possible such feature for HD 220061. New observations were made at the Haute-Provence Observatory in 1994 and 1995 and we present here evidence for the presence of circumstellar components around some other Bootis stars.
Since publication of Paper I, many papers on the Bootis stars have been published, among which we may mention those from Holweger & Rentzsch-Holm (1995) and Andrillat et al. (1995). Holweger and Rentzsch-Holm report on high-resolution observations of the CaII-K line in two samples of A stars, Bootis and dusty normal A stars, finding CS components for five out of eleven Bootis stars. Their conclusion is that the presence of detectable amounts of circumstellar gas in A stars is rare among chemically normal A stars. However the Bootis stars are metal-deficient and nearly half of their sample are surrounded by circumstellar gas. A similar conclusion is reached by Andrillat et al. (1995), who observed a sample of 20 Bootis stars in three wavelength regions in the near infrared. Seven stars of this sample exhibit evidence of shells. It is also important to pay attention to temporal variations of for both the stellar and circumstellar lines. Many authors have reported lately on the pulsation and variability of some Bootis stars (Weiss et al. 1994; Kuschnig et al. 1994a,b; Paunzen et al. 1995a,b; Paunzen 1995; Bohlender et al. 1996) and Holweger & Rentzsch-Holm (1995) have mentioned a variation of the CS component of HD 111786 between 1990 and 1994. At the earlier date the CS component is slightly blue shifted, while at the second date it is red shifted. Faraggiana et al. (1997) consider this star to be a spectroscopic binary whose Bootis primary has a high rotation speed, while the secondary has an F type and a slow rotation; one of the two components pulsates.