For many years the nature of the Bootis stars has been controversial.
About 20% of all PopulationI
A-type stars show abundance peculiarities. Most of these CP stars are
characterized by strong overabundances of iron peak elements (Jaschek &
Jaschek 1995). In contrast, the
Bootis stars are metal poor, Populaton
I, A and early F-type stars.
Unfortunately, these astrophysically interesting stars are quite
rare; the most recent list of confirmed members (Gray & Corbally
1993) had only 20 members. A recent paper (Paunzen et al.
1997) attempted to expand this number by a critical assessment of
the literature resulting in a total of 45 members and candidate members.
This small sample of stars still makes a sound statistical analysis
difficult. Therefore we have started a spectroscopic survey
for new members in the galactic field, open clusters and associations.
The discovery of
Bootis stars in open clusters and associations is especially
important because of the possibility of age determination,
thus providing the means to distinguish between the two proposed
theories - the diffusion/mass loss theory (Michaud & Charland
1986) and the accretion
theory (Venn & Lambert 1990). Candidate
Bootis stars
were discovered in the Orion OB1 association (three
new
Bootis stars found), NGC2264 (two candidates) and
the galactic field (five new
Bootis stars).
Additional observations in NGC2232 (age
;
Mermilliod 1981)
and NGC2301 (age
108yr; Mermilliod 1981)
yielded a null result. We have been able to confirm a number of the
candidate members proposed in Paunzen et al. (1997).