Wednesday 09 Jan 2019: [Seminar] Exoplanet atmospheres at high spectral resolution
Dr Matteo Brogi - University of Warwick
4th Floor, Physics Building 14:30-15:30
After only two decades from the first discoveries, we know today thousands of planets orbiting other stars. Although this wealth of exoplanets allows us to draw detailed statistical conclusions about their demographics, relatively little is known yet about their intrinsic properties (composition, internal and atmospheric structure, etc.). The latter are crucial to determine how planets form, evolve, and if they could possibly harbour life.
The best chance to characterize exoplanets is by studying their atmospheres, which is possible nowadays with a range of observational techniques. In this talk I will focus on ground-based high-resolution (R>20,000) spectroscopy, which allows us to resolve molecular bands into the individual spectral lines, and extract the information from observed spectra through cross correlation with model templates. In this way, species can be detected robustly and their relative abundances determined. As an added bonus, due to the direct detection of the planet orbital motion, the chances of contamination from spurios signals are greatly reduced.
I will review the major breakthroughs achieved in recent years, among which are the first atmospheric detections for non-transiting planets, and the unprecedented measurements of their true masses and orbital inclinations. I will present current efforts focusing on measuring rotational rates and winds of giant planets, combining high-resolution spectroscopy with low resolution spectroscopy from space, and extending the sensitivity of the method to smaller and fainter planets. This will allow us to characterize the planets found by the TESS mission and, once the next-generation of ELTs will be online, to target potentially-habitable worlds orbiting M-dwarfs.