Classificação de estrelas b da campanha 11 - Kepler/k2

Abstract

The study of B star variability is a field that showed rapid expansion in the last decade. New behaviors are being discovered thanks to the unprecedented photometric precision achieved with spatial telescopes, mainly the CoRoT, led by CNES and ESA, and the Kepler, from NASA. An extensive effort was made to analyze and classify the light curves of B stars in the original Kepler field. However the same cannot be said for the B stars observed in de K2 mission from Kepler. This dissertation intends to cover this gap, analyzing the light curves of 168 stars observed by Kepler, in the campaign 11 of its K2 mission, and present the data in a comprehensible way, align with the recent literature on the matter. These are mainly B stars, with some early A or late O type. The variability analyses reveal SPB stars as the dominant group, followed by stars with variation due to rotation or binarity. Some 𝛽 Cepheid stars were found too. On the ground, spectra for 60 objects were obtained, allowing the determination of the stellar parameters and confront the variability assigned with the theoretical expectations. In addition to that, spectra were obtained in the H𝛼 region for 103 objects, to track stars with know emission line and search for new ones. With the H𝛼 profile of the emission stars, the approximate inclination was determined. Emission line was discovered in four new stars. P Cygni profile was noted in one of the stars with know emission line, and this also displayed the most robust variability between those analyzed.