Institute of Astronomy

Importance of Accurate Molecular Spectroscopy for Characterizing Exoplanetary Atmospheres

SpeakerTalk DateTalk Series
Christina Hedges28 July 2014Across HR 2014 Posters


Recent advances in exoplanetary spectroscopy over the past few years have opened up detailed characterization of exoplanetary atmospheres. Using spectroscopic observations it is possible to determine elemental and molecular abundances within the atmospheres of exoplanets with high statistical significance. These data can be used to further investigate various atmospheric processes, such as non-equilibrium chemistry, temperature inversions, atmospheric dynamics, and the presence of clouds in these planets. Critical to the interpretation of spectra, however, is the reliability of the fundamental input parameters to the models such as the atomic and molecular absorption cross-sections derived from the corresponding line-lists. With transition line-list data being recently updated for many of the relevant molecules, at much higher temperatures than was previously available, it is now possible to scrutinise the transition features of these molecules and the application of high temperature line-lists to atmospheric studies. Molecular transition features vary under different temperature and pressure regimes and this variance affects the detection of atmospheric lines in given bandpasses. In this work we demonstrate the importance of accurate line-lists and broadening parameters for calculating reliable molecular cross sections and discuss their implications for abundance determination in exoplanetary atmospheres. We present an investigation into the relevant molecules for atmospheric studies and how their absorption features correlate with the bandpasses of instruments involved in exoplanet spectroscopy. We identify optimal bandpasses on current and future instruments available for atmospheric characterisation of exoplanets and discuss the impact on future work.