Since the discovery of the first exoplanet around a sun-like star over 2 decades ago, enormous progress has been made. The number of known exoplanets has increased to over 3000 today. Even more interestingly, we have started to probe the atmospheres of some these planets using telescopes in space and on the ground.
In most cases, these studies focus on transiting planets where we can either study the atmosphere in transmission as it passes between the Earth and the star, which allows a direct determination of the composition and extend of the atmosphere, or by looking for the light emitted by the planet. To measure the light coming from the planet we can either observe the secondary eclipse, when the planet passes behind the star, or by measure the phase-curve variations as the planet orbits its star. In the latter case, we are looking at differences in the emission between the day- and night-side as they rotate in and out of view as the planet orbits its star.
By observing the systems at a high spectral resolution, we can directly separate the atomic and molecular lines from the planet from lines arising in its host-star or the Earth’s atmosphere by taking advantage of the Doppler shift of the planet’s lines. This allows us to determine both the composition and orbital velocity of the planet.
The aim of this project is to take advantage of new instruments, such as CRIRES+ and ESPRESSO, that are coming online, and use these high-resolution spectrographs to study the atmospheres of exoplanets. This will both increase the sample of characterised atmospheres, as well as probe the atmospheres over a wider wavelength range, thereby targeting more species (e.g. CO, CO2, H2O, TiO, VO, …) and allowing a better determination of the planet’s chemical composition. As part of this project we will improve current techniques, and develop new ones. These techniques will act as path-finders for the efficient exoplanet characteristation with the next generation of large telescopes, such as the E-ELT, that may be able to provide the first detection of life outside the Solar System.
Supervisor: Dr. Ernst de Mooij