Abstract

Transiting planets are of particular interest for exoplanet science. During transit the upper atmospheric layers are penetrated by the host star’s light enabling us to measure the atmospheric composition at the terminator region as a color dependent variation in the occultation depth. One of the biggest remaining challenges of multi-color transit observations is the removal of systematic noise signals. Such signals are frequently found to distort light curves of both ground-based and space-based origin. In many cases their source is not well understood. Our group uses the ground-based facilities ESO/VLT with the FORS2 instrument and the Spanish 10-meter telescope GranTeCan with the OSIRIS instrument to probe the atmosphere of hot Jupiters with the technique of multi object spectrophotometry. I will address our new findings regarding the source and nature of instrument specific systematics we found to commonly affect data taken with these two instruments. Furthermore, I will introduce our approach to the correction of these noise signals, which allows us to retrieve high quality results. As an example I will present the transmission spectra of the two hot Jupiters WASP-17b and HAT-P-32b which we obtained in the broad optical wavelength region between 500 – 1000 nm where hot Jupiter atmospheres are predicted to exhibit sodium, potassium, water and titanium/vanadium oxide absorption. The abundance of these atmospheric species is of particular interest, as they serve as good indicators for the prevalent temperature and can help to shed light on the mechanisms of heat re-distribution between the planet’s day and night side.

Presentation

Poster