JultikaUniversity of Oulu repository

Abstract

Extrasolar planets, also shorter called exoplanets, are one of the newest and most rapidly growing fields of astronomy today. Exoplanets are planets which orbit a star outside of our Solar system, in other words they orbit other stars than the Sun. The first ever detection of an exoplanet was back in the year 1992 around a pulsar but the first exoplanet which orbited a normal star was discovered in the year 1995 and as of today 4183 exoplanets have been detected. The majority of extrasolar planets are found with the transit method.

There are different techniques on how exoplanets can be detected. Discoveries were first made mainly with the radial velocity technique until the Kepler Telescope became active in the year 2009 and multiplied discoveries with the transit method. In the future there will be many new campaigns to discover new exoplanets such as the James Webb Space Telescope (JWST), PLATO and ARIEL. By new campaigns it is expected that exoplanet discoveries will be multiplied.

Planetary rings in the Solar system consist of many small bodies orbiting their planets in size from micrometers to tens of meters. Their composition varies from water-ice to silicates. In our own Solar system each giant planet has its own ring system and therefore it is reasonable to expect that planets orbiting other stars could have rings too.

We present the background of exoplanet and exo-ring research, light curves and theoretical aspects of ring systems. Then we get acquainted with the generation of synthetic light curves. We discuss the light curve data available online and how the exoplanet candidates for this thesis have been selected. Finally we present light curves of selected exo-ring candidates and examine and compare them. The ultimate objective of this thesis is to search literature on the topic and screen it to the study, examine the databases, review it and also discuss it and present the models made for the thesis. In practical point of view first we search for the light curve data available online, examine it to find features of rings and compare the findings to the modelled synthetic light curves and discuss results.