The Exoplanets & Exoclimes Group is based at the University of Bern, Switzerland, and is supported by the Swiss National Science Foundation, the PlanetS NCCR and the MERAC Foundation.
Exoclimes Group posts
In our weekly journal club we reviewed Benneke 2015 (Strict Upper Limits on the Carbon-to-Oxygen Ratios of Eight Hot Jupiters from Self-Consistent Atmospheric Retrieval, under review at ApJ). We widely discuss the method used by the author a bayesian analysis (Nested Sampling algorithm) coupled with a self-consistent model. Combining the physical insight given by forward models with the rigorous treatment of uncertainties of a Bayesian analysis represent a long-term goal in atmospheric retrieval. We mainly debate on the robustness of the method.
Last Thursday (23/04/2015) during journal club we reviewed the work from M. Takagi et. al. 2009 entitled “Influence of CO2 line profiles on radiative and radiative‐convective equilibrium states of the Venus lower atmosphere” . In this work the authors developed a radiative-convective model to explore mainly the impact of different CO2 line shapes suggested in the literature on the radiative-convective temperature profile of the Venus lower atmosphere. The CO2 absorption line shape is still poorly understood. It is known that these lines are sub-lorentzians far from the line centre but their parameterisation is still undetermined. The results were shown to be very sensitive to initial assumptions. We also discussed what would be the impact of poorly parameterised line shapes on exoplanet studies where there is no observational data to calibrate the models.
The Leiden professor, astrophysicist and computer scientist Simon Portegies Zwart visited the University of Bern and delivered a special seminar on Sedna and N-body simulations.
Simon Grimm has just successfully defended his Ph.D thesis at the University of Zurich, entitled, "GPU Computational Methods for Planet Formation and Exoplanet Characterisation." Congrats, Simon!
In today's journal club, we reviewed Showman et al. (2014) "Three-dimensional Atmospheric Circulation of Warm and Hot Jupiters: Effects of Orbital Distance, Rotation Period, and Non-Synchronous Rotation. By simple timescale analysis of comparing the radiative time and solar day, the circulations are divided into two regimes: high irradiation and slow rotation regime exhibits equatorial superrotating jet, while lower irradiation and faster rotation results in larger latitudinal temperature gradient and off-equatorial eastward jets. 3D numerical simulations using the SPARC/MITgcm show agreement with the theoretical predictions.
Kevin Schawinski (ETH Zurich, Institute for Astronomy) visited the University of Bern and delivered a CSH Colloquium on the growth of black holes and their environments. Using an array of astronomical observations, Schawinski and his team were able to constrain the duration of the AGN (active galactic nucleus) phase of galaxies.
WASP-80b appears to have a dayside atmosphere resembling that of a T4 dwarf, based on warm Spitzer photometry.
Michael Line (UCSC) visited the University of Bern and delivered a CSH Colloquium reviewing the use of atmospheric retrieval in understanding transiting exoplanets, directly imaged exoplanets and brown dwarfs.
Antonija Oklopcic (Caltech) visited the University of Bern and gave a seminar on computing methane opacities at high temperatures and wavenumbers using a Monte Carlo technique.
Kevin Heng has agreed to join Molecular Astrophysics for a year as a Handling Editor. The Editor-in-Chief is the chemist and astronomer Xander Tielens of Leiden University.