Estrelas do tipo A da Campanha 8 da Missão Kepler K2

Abstract

Searching to improve the statistics of seismological parameters of stars of type A, we this work we present the analysis of spectroscopic and photometric data of eight stars observed in the direction of the Galactic Pole during the Kepler mission Campaign 8, proposed by our research group. The photometric observation occurred between January and March 2016. Frequency analysis of the eight light curves was made using the CLEANEST and Period04 algorithm. In addition to the photometric data, ground-based spectroscopy was done at the OPD/LNA in October 2015 with the Zeiss Telescope (0.6m) and in August 2016 with the Perkin-Elmer Telescope (1.6m). Spectroscopic information enhances the data from thesatellite’slightcurves,allowingthecharacterizationoftheinternalstellarstructure. Spectral characterization was done using Spectroscopy Made Easy (SME). Parameters such as mass, radius and luminosity were obtained using the Code d Évolution Stellaire Adaptatif et Modulaire (CESAM) and Porto Oscillations Code (POSC) grids, allowing to generate evolutionary models for the eight stars. Stars of spectral type B are often erroneously classified as stars of spectral type A, when only photometry data is used for classification. As an example, we have the stars: Epic220679442 and Epic220607132. Photometrically classified as spectral type A0, revealed through spectral analysis, to be spectral type B9V. Epic220532854 is a binary, Epic220466722 is a δ Scuti and Epic220679442 has photometric variations and spectroscopy data reveals pronounced silicon line (SiII λ4128), characteristic presented by the class peculiar stars Ap magnetic.