Trust, O. ; Jurua, E. ; De Cat, P. ; Joshi, S. ; Lampens, P.

published in Monthly Notices of the Royal Astronomical Society, 504, pp. 5528-5542

Abstract: The nominal Kepler mission provided very high-precision photometric data. Using these data, interesting phenomena such as spots, and “hump and spike” features were observed in the light curves of some normal A and metallic lined A stars (Am stars). However, the effects of such phenomena on the chemical peculiarity of the Am stars are still unclear. In order to make progress in finding the solution, its important to collect high-resolution spectroscopic data to determine their fundamental parameters and individual chemical abundances. In this paper, we present a spectroscopic study of a sample of "hump and spike" stars in the nominal Kepler field. We used data collected with the High Efficiency and Resolution Mercator Échelle Spectrograph (HERMES). We determined the spectral type of these stars and obtained the atmospheric stellar parameters such as effective temperatures, surface gravities, projected rotational, microturbulent and radial velocities. We also performed a detailed individual chemical abundance analysis for each target. We confirmed KIC3459226 and KIC6266219 as Am stars, KIC9272082 and KIC9349245 as marginal Am stars, while KIC4567097, KIC4818496, KIC5524045, KIC5650229 and KIC7667560 are non-Am stars. To estimate their evolutionary phases, all the stars were placed in the Hertzsprung-Russell (HR) diagram. Based on its spectral classification and chemical abundance pattern, we confirmed KIC6266219 (previously treated as chemically normal) as an Am star (kA3hA7mF1).

Keyword(s): Stars: chemically peculiar ; Stars: rotation ; Stars: starspots ; Stars: general ; Techniques: spectroscopic
DOI: 10.1093/mnras/stab1149