Based on observations obtained at the Canada–France–Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France and the University of Hawaii.
Accurate fundamental parameters and detailed abundance patterns from spectroscopy of 93 solar-type Kepler targets
Article first published online: 11 MAY 2012
© 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS
Monthly Notices of the Royal Astronomical Society
Volume 423, Issue 1, pages 122–131, June 2012
How to Cite
Bruntt, H., Basu, S., Smalley, B., Chaplin, W. J., Verner, G. A., Bedding, T. R., Catala, C., Gazzano, J.-C., Molenda-Żakowicz, J., Thygesen, A. O., Uytterhoeven, K., Hekker, S., Huber, D., Karoff, C., Mathur, S., Mosser, B., Appourchaux, T., Campante, T. L., Elsworth, Y., García, R. A., Handberg, R., Metcalfe, T. S., Quirion, P.-O., Régulo, C., Roxburgh, I. W., Stello, D., Christensen-Dalsgaard, J., Kawaler, S. D., Kjeldsen, H., Morris, R. L., Quintana, E. V. and Sanderfer, D. T. (2012), Accurate fundamental parameters and detailed abundance patterns from spectroscopy of 93 solar-type Kepler targets. Monthly Notices of the Royal Astronomical Society, 423: 122–131. doi: 10.1111/j.1365-2966.2012.20686.x
Based on observations with the 2-m Telescope Bernard Lyot funded by the CNRS Institut National des Sciences de l’Univers.
- Issue published online: 30 MAY 2012
- Article first published online: 11 MAY 2012
- Accepted 2012 February 2. Received 2012 January 30; in original form 2011 November 6
- stars: abundances;
- stars: atmospheres;
- stars: fundamental parameters;
- stars: solar-type
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 α 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 i–Fe ii balance, although we find a small systematic offset of 0.08 dex (asteroseismic log g values are lower). The abundance patterns of metals, α 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 α-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.