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|Title:||CAOS spectroscopy of Am stars Kepler targets||Authors:||CATANZARO, Giovanni
|Issue Date:||2015||Journal:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY||Number:||451||Issue:||1||First Page:||184||Abstract:||The Kepler space mission and its K2 extension provide photometric time series data with unprecedented accuracy. These data challenge our current understanding of the metallic-lined A stars (Am stars) for what concerns the onset of pulsations in their atmospheres. It turns out that the predictions of current diffusion models do not agree with observations. To understand this discrepancy, it is of crucial importance to obtain ground-based spectroscopic observations of Am stars in the Kepler and K2 fields in order to determine the best estimates of the stellar parameters. In this paper, we present a detailed analysis of high-resolution spectroscopic data for seven stars previously classified as Am stars. We determine the effective temperatures, surface gravities, projected rotational velocities, microturbulent velocities and chemical abundances of these stars using spectral synthesis. These spectra were obtained with CAOS, a new instrument recently installed at the observing station of the Catania Astrophysical Observatory on Mt Etna. Three stars have already been observed during quarters Q0-Q17, namely: HD 180347, HD 181206 and HD 185658, while HD 43509 was already observed during K2 C0 campaign. We confirm that HD 43509 and HD 180347 are Am stars, while HD 52403, HD 50766, HD 58246, HD 181206 and HD 185658 are marginal Am stars. By means of non-LTE (local thermodynamic equilibrium) analysis, we derived oxygen abundances from O I λ7771-5 Å triplet and we also discussed the results obtained with both non-LTE and LTE approaches.||Acknowledgments:||The authors wish to thank Dr L. Balona and Dr P. G. Prada Moroni for helpful discussions. This publication makes use of VOSA, developed under the Spanish Virtual Observatory project supported from the Spanish MICINN through grant AyA2011-24052. This research has made use of the SIMBAD data base and VizieR catalogue access tool, operated at CDS, Strasbourg, France. This publication makes use of data products from the Wide-field Infrared Survey Explorer , which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. Atomic data compiled in the DREAM data base (Biemont, Palmeri Quinet 1999 ) were extracted via VALD (Kupka et al. 1999 , and references therein).||URI:||http://hdl.handle.net/20.500.12386/23333||URL:||https://academic.oup.com/mnras/article/451/1/184/1366368||ISSN:||0035-8711||DOI:||10.1093/mnras/stv952||Bibcode ADS:||2015MNRAS.451..184C||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
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