The Rossiter-McLaughlin effect in exoplanets

Abstract

Historically, one of the burning questions of astronomy deals with the exoplanet’s topic, in other words the search of any planet beyond the Solar System. In this project we introduce a first theoretical chapter in which the definition of exoplanet is stipulated, the main detection techniques described and a brief analysis of the instruments used. The aim of this study is studying the Rossiter-McLaughlin (RM) effect in WASP-69b using CARMENES data. The RM is an anomaly of the RV due the blockage of part of the host star’s light. It can be detected with high-resolution spectrographs, such as HARPS and CARMENES, that are enough accurate to detect the Doppler shifts in the spectrum of the star caused by the planet’s motion. The RM effect can be used to study and characterise the atmosphere of exoplanets, although it is difficult to resolve the spectral lines stems from high stellar activity and telluric contamination from the terrestrial atmosphere. We will observe how the telluric contamination and the stellar activity alter the RV data and the RM parameters. To do this, we will use a pipeline called SERVAL, removing the highly contaminated regions to compare if this has an improvement on the results. The data used are from two transit observations of WASP-69b with the CARMENES spectrograph, located at the Calar Alto observatory. In addition, we will measure the chromatic RM effect of WASP-69b following the method described by DiGloria et al. (2015). In the results we can observe that the errors are clearly reduced when we exclude the contaminated orders, as expected. However, for the chromatic RM effect the errors are too large to conclude something precise. To yield good results, and get accurate atmospheric properties, more transits are needed as well as high resolution observations with larger telescopes.