New Spectroscopic Classifications of 35 chemically peculiar candidate stars

PAUNZEN, E.; NETOPIL, M.; PINTADO, O. I.; RODE-PAUNZEN, M.

ASTRONOMISCHE NACHRICHTEN

WILEY-V C H VERLAG GMBH

Año: 2011 vol. 32 p. 77 - 82

0004-6337

The chemically peculiar (CP) stars of the upper main sequence are perfect tracers for several astrophysical processes.Their study especially in open clusters further helps to establish their evolutionary status. The latter is most important tounderstand the origin and evolution of the CP phenomenon, i.e. the connection between diffusion and a stellar magneticfield. There are two important topics, we cover with this paper. First of all, we investigate the reliability of the CCD
a photometry for fainter objects in open clusters. The latter method is able to detect CP stars very efficiently, butstill a spectroscopic verification is needed to verify the photometric candidates. On the other hand, already publishedspectral classifications on the basis of photographic plates and prismtechnology have to be tested withmodern instruments.Classification resolution spectroscopy is presented for thirty five bona-fide CP candidates. Twenty six of them are locatedwithin the boundaries of fourteen open clusters, for which we also investigated their membership probabilities. Apart fromfive objects, they seem to be members of the respective clusters. The objects were classified in the framework of a refinedMorgan-Keenan system with the extension of well established CP star spectra. We confirm the CP nature of all but onetarget. The results of
a photometry and the spectral classifications are in excellent agreement. For the cluster memberswe find a continuous sequence of CP stars from 10 to 850Myr, the whole range of investigated cluster ages.