masterThesis
Análise wavelet em curvas de luz estelares de sistemas binários da missão espacial CoRoT
Fecha
2015-09-16Registro en:
LIRA, Suzierly Roque de. Análise wavelet em curvas de luz estelares de sistemas binários da missão espacial CoRoT. 2015. 95f. Dissertação (Mestrado em Física) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2015.
Autor
Lira, Suzierly Roque de
Resumen
Binary systems are key environments to study the fundamental properties of stars. In this
work, we analyze 99 binary systems identified by the CoRoT space mission. From the study of the
phase diagrams of these systems, our sample is divided into three groups: those whose systems are
characterized by the variability relative to the binary eclipses; those presenting strong modulations
probably due to the presence of stellar spots on the surface of star; and those whose systems have
variability associated with the expansion and contraction of the surface layers.
For eclipsing binary stars, phase diagrams are used to estimate the classification in regard
to their morphology, based on the study of equipotential surfaces. In this context, to determine the
rotation period, and to identify the presence of active regions, and to investigate if the star exhibits
or not differential rotation and study stellar pulsation, we apply the wavelet procedure.
The wavelet transform has been used as a powerful tool in the treatment of a large number
of problems in astrophysics. Through the wavelet transform, one can perform an analysis in
time-frequency light curves rich in details that contribute significantly to the study of phenomena
associated with the rotation, the magnetic activity and stellar pulsations. In this work, we apply
Morlet wavelet (6th order), which offers high time and frequency resolution and obtain local
(energy distribution of the signal) and global (time integration of local map) wavelet power spectra.
Using the wavelet analysis, we identify thirteen systems with periodicities related to the rotational
modulation, besides the beating pattern signature in the local wavelet map of five pulsating stars
over the entire time span.