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Accurate fundamental parameters and detailed abundance patterns from spectroscopy of 93 solar-type Kepler targets

TitreAccurate fundamental parameters and detailed abundance patterns from spectroscopy of 93 solar-type Kepler targets
Type de publicationJournal Article
Year of Publication2012
AuteursBruntt, H, Basu, S, Smalley, B, Chaplin, WJ, Verner, GA, Bedding, TR, Catala, C, Gazzano, JC, Molenda-Zakowicz, J, Thygesen, AO, Uytterhoeven, K, Hekker, S, Huber, D, Karoff, C, Mathur, S, Mosser, B, Appourchaux, T, Campante, TL, Elsworth, Y, Garcia, RA, Handberg, R, Metcalfe, TS, Quirion, PO, Regulo, C, Roxburgh, IW, Stello, D, Christensen-Dalsgaard, J, Kawaler, SD, Kjeldsen, H, Morris, RL, Quintana, EV, Sanderfer, DT
JournalMonthly Notices of the Royal Astronomical Society
Date PublishedJun
ISBN Number0035-8711
Numéro d'accèsWOS:000304599100010

We present a detailed spectroscopic study of 93 solar-type stars that are targets of the NASA/Kepler mission and provide detailed chemical composition of each target. We find that the overall metallicity is well represented by Fe lines. Relative abundances of light elements (CNO) and a elements are generally higher for low-metallicity stars. Our spectroscopic analysis benefits from the accurately measured surface gravity from the asteroseismic analysis of the Kepler light curves. The accuracy on the log g parameter is better than 0.03 dex and is held fixed in the analysis. We compare our Teff determination with a recent colour calibration of VT-KS [TYCHO V magnitude minus Two Micron All Sky Survey (2MASS) KS magnitude] and find very good agreement and a scatter of only 80 K, showing that for other nearby Kepler targets, this index can be used. The asteroseismic log g values agree very well with the classical determination using Fe iFe ii balance, although we find a small systematic offset of 0.08 dex (asteroseismic log g values are lower). The abundance patterns of metals, a elements and the light elements (CNO) show that a simple scaling by [Fe/H] is adequate to represent the metallicity of the stars, except for the stars with metallicity below -0.3, where a-enhancement becomes important. However, this is only important for a very small fraction of the Kepler sample. We therefore recommend that a simple scaling with [Fe/H] be employed in the asteroseismic analyses of large ensembles of solar-type stars.

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