ETH Exoplanets & Habitability Seminars Fall Semester 2021
Exoplanets Seminars Fall Semester 2021
The Exoplanets Seminars will be held digitaly via Zoom. Please contact keuferpc@phys.ethz.ch or gcugno@phys.ethz.ch for the zoom details.
Wednesday, November 17th, 2021, 13:00-14:00 h, Zoom
Speaker: Valentin Christiaens
Title: Imaging giant planet formation
Abstract: The new generation of infrared high-contrast imagers and sub-mm interferometer has been revolutionizing our view of planet formation for almost a decade. Protoplanetary discs - the birth cradles of planets, have now been imaged at a high level of detail, revealing a wealth of structures including cavities, annular gaps, spiral arms, shadows and asymmetries. In order to connect these structures to forming planets and provide the most stringent constraints to planet formation theories, we need to directly image newborn planets in these discs. I will first highlight the challenges involved in this endeavour, and will then focus on the specific case of PDS 70, for which I will summarize what has been learned from 3 years of follow-up and characterisation of this system. I will also present ongoing work on other promising sources, and briefly describe future prospects for the field, considering the advent of the James Webb Space Telescope and Extremely Large Telescopes.
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Please save the date:
Wednesday, November 24th, 2021, 17:00-18:00 h, Zoom
Speaker: Raissa Estrela
Title: Habitability
Abstract: will follow
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Past Talks:
Wednesday, November 10th, 2021, 13:00-14:00 h, Zoom meeting
Speaker: Niall Whiteford
Host: Polychronis Patapis
Title: Using retrievals to unlock the cloudy mysteries of gas giant planets (Atmospheric retrieval and modelling)
Abstract: Retrieval methods are increasingly being employed for analysis of directly imaged exoplanetary atmospheres. This technique statistically explores a variety of potential bulk and atmospheric model parameters that combine to best fit an observed spectrum. While this technique has produced ground breaking research, retrieving clouds remains a significant and complex challenge. TauREx3 (Tau Retrieval of Exoplanets) is a Bayesian retrieval suite designed to be applied to spectroscopic observations of extrasolar planetary atmospheres. We have expanded TauREx3 for analysis of near-infrared spectroscopy for a sample of directly imaged gas giant exoplanets and brown dwarfs that encompasses the L and T spectral types. This includes Beta Pic b, HR 8799de, PSO 318, VHS 1256 b and 51 Eri b. Using this sample, we have tested different cloud parameterisations ranging from a simplistic power law to a more robust Mie opacity regime. We explored the implementation of non-uniform clouds, motivated by the substantial variability observed in relations to several of the aforementioned objects. We have also probed the impact of using different cloud particle size distributions and temperature-pressure profiles in an effort to explore the biases different retrieval setups may introduce. This testing of retrieval frameworks is essential given the upcoming launch of JWST and the subsequent high-quality data it will provide. In this talk I will present a summary of the novel retrieval results from this study.
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