[en] The Kepler space mission provided near-continuous and high-precision photometry of about 207,000 stars, which can be used for asteroseismology. However, for successful seismic modelling it is equally important to have accurate stellar physical parameters. Therefore, supplementary ground-based data are needed. We report the results of the analysis of high-resolution spectroscopic data of A- and F-type stars from the Kepler field, which were obtained with the HERMES spectrograph on the Mercator telescope. We determined spectral types, atmospheric parameters and chemical abundances for a sample of 117 stars. Hydrogen Balmer, Fe I, and Fe II lines were used to derive effective temperatures, surface gravities, and microturbulent velocities. We determined chemical abundances and projected rotational velocities using a spectrum synthesis technique. The atmospheric parameters obtained were compared with those from the Kepler Input Catalogue (KIC), confirming that the KIC effective temperatures are underestimated for A stars. Effective temperatures calculated by spectral energy distribution fitting are in good agreement with those determined from the spectral line analysis. The analysed sample comprises stars with approximately solar chemical abundances, as well as chemically peculiar stars of the Am, Ap, and Lambda Boo types. The distribution of the projected rotational velocity, Vsini, is typical for A and F stars and ranges from 8 to about 280 km/s, with a mean of 134 km/s.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Niemczura, E.
Murphy, S. J.
Smalley, B.
Uytterhoeven, K.
Pigulski, A.
Lehmann, H.
Bowman, D. M.
Catanzaro, G.
van Aarle, E.
Bloemen, S.
Briquet, Maryline ; Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Molenda- Z˙akowicz J., Latham D.W., Catanzaro G., Frasca A., Quinn S. N., 2011, MNRAS, 412, 1210
Monet D. G. et al., 2003, AJ, 125, 984
Moravveji E., Guinan E. F., Shultz M., Williamson M. H., Moya A., 2012, ApJ, 749, 74
Mosser B. et al., 2012, A&A, 548, A10
Munari U., Zwitter T., 1997, A&A, 318, 26
Murphy S. J., 2014, PhD thesis, Univ. Central Lancashire
Murphy S. J., Bedding T. R., Niemczura E., Kurtz D.W., Smalley B., 2015, MNRAS, 447, 3948
Neuteufel R., Weiss W., Handler G., 2013, Astron. Nachr., 334, 638
Niemczura E., Połubek G., 2006, in Fletcher K., Thompson M., eds, ESA SP-624, Proc. SOHO 18/GONG 2006/HELAS I, Beyond the Spherical Sun. Sheffield, UK, p. 120
Niemczura E., Morel T., Aerts C., 2009, A&A, 506, 213
Noci G., Pomilia A., Ortolani S., 1986, in Zeilik M., Gibson D. M., eds, Lecture Notes in Physics, Vol. 254, Springer-Verlag, Berlin, Heidelberg, New York, p. 130
Paunzen E., Iliev I. K., Fossati L., Heiter U.,Weiss W.W., 2014, A&A, 567, AA67
Przybilla N., Butler K., Becker S. R., Kudritzki R. P., Venn K. A., 2000, A&A, 359, 1085
Raskin G. et al., 2011, A&A, 526, A69
Richard O., 2005, EAS Publ. Ser. Vol. 17, p. 43
Rowe J. F. et al., 2006, Commun. Asteroseismology, 148, 34
Royer F., 2009, The Rotation of Sun and Stars, Lecture Notes in Physics, Vol. 765. Springer, Berlin, p. 207
Royer F., Zorec J., Gómez A. E., 2007, A&A, 463, 671
Royer F. et al., 2012, SF2A-2012, Proc. Ann. Meeting French Soc. Astron. Astrophys. p. 389
Smalley B., 2004, in Zverko J., Ziznovsky J., Adelman S. J., Weiss W. W., eds, Proc. IAU Symp., 224, Observations of convection in A-type stars. Cambridge Univ. Press, Cambridge, p. 131
Takeda Y., 1995, PASJ, 47, 287
Takeda Y., Han I., Kang D. I., Lee B. C., Kim K.M., 2008, J. Korean Astron. Soc., 41, 83
Takeda Y., Kang D. I., Han I., Lee B. C., Kim K. M., 2012, PASJ, 64, 38
Talon S., Richard O., Michaud G., 2006, ApJ, 645, 634
Tkachenko A., Van Reeth T., Tsymbal V., Aerts C., Kochukhov O., Debosscher J., 2013a, A&A, 560, A37
Tkachenko A., Lehmann H., Smalley B., Uytterhoeven K., 2013b, MNRAS, 431, 3685
Trampedach R., Stein R. F., 2011, ApJ, 731, 78
Turcotte S., 2003, in Balona L. A., Henrichs H. F., Medupe R., eds, ASP Conf. Ser. Vol. 305, Magnetic Fields in O, B and A Stars: Origin and Connection to Pulsation, Rotation and Mass Loss. Astron. Soc. Pac., San Francisco, p. 199
Uytterhoeven K., 2014, in Determination of Atmospheric Parameters of B-, A-, F- and G-Type Stars, Springer Series:GeoPlanet: Earth and Planetary Sciences, Springer International Publishing, p. 1
Uytterhoeven K. et al., 2010, Astron. Nachr., 331, 993