Análise da variação do Período Orbital de Kepler-451: candidato a sistema multiplanetário em uma configuração circumbinária

Abstract

Orbital period variations in binary systems can arise from various mechanisms, such as gravitational wave emission, magnetic braking, mass transfer between components, apsidal motion, and gravitational interaction with external bodies. These variations are, therefore, crucial for studying various physical phenomena as well as the stellar system’s evolution itself. In this context, this work aims to study the orbital period variation of the eclipsing binary system Kepler-451. This system, which has a tight orbit (orbital period of approximately 3h), consists of a B-type subdwarf (sdB) and a low-mass main-sequence star (M dwarf). Kepler-451 was observed from 2009 to 2024 by the Kepler and TESS satellites, providing excellent temporal coverage. We used these data to measure the times of primary eclipses and fitted a linear ephemeris to the results. The residuals, also known as the (O − C) diagram, showed a complex variation with at least two periodic components. Consequently, we analyzed the (O − C) diagram using two models: (i) two and (ii) three circumbinary bodies. The results for the minima masses and orbital periods derived from model (i) were 1.87 ± 0.11 and 2.35 ± 0.12 MJ, and approximately 400 and 4000 days for the inner and outer bodies, respectively. For model (ii), the results for the same parameters were 1.87 ± 0.10; 1.89 ± 0.35 and 3.66 ± 0.46 MJ, with orbital periods of approximately 400, 1800, and 4000 days for the inner, intermediate, and outer bodies, respectively. Although preliminary, our result for the outer planet derived in both models is entirely new.