Invited comunication
P. Machado, R. Gonçalves, T. Widemann, G. Gilli
Abstract
Understanding our Solar System Planetary Atmospheres is a significant step forward for paving the way for future studies of Extrasolar Planets’ atmospheres. Notably, Venus and Mars are natural comparative laboratories to investigate diversity of circulation regimes of terrestrial planets’ atmospheres. In this context, comparative studies are essentials to understand the evolution of climate on Earth, both in the past and in the future. Notably, Venus and Mars are natural comparative laboratories to investigate diversity of circulation regimes of terrestrial planets’ atmosphere. Venus for example, is Earth’s closest sibling but it has ended up with a radically di↵erent climate. Venus atmospheric science is thus increasingly important in an era in which we are trying to understand the divergent evolutionary outcomes for terrestrial planets, whether we are considering the future of our Earth or the habitability in other planetary systems.
We will present a study based on large scale and small scale processes going on the middle/ upper atmosphere of Venus and Mars combining wind measurements and 3D model simulations.
Venus is a slowly rotating planet with a dense atmosphere. The mechanisms for the generation and maintenance of superrotation are still unclear and no model has been able to successfully reproduce its circulation in decades (Lebonnois 2013). A proper monitoring of Venus winds is crucial towards a full understanding of this phenomena. With this aim, we intend to conduct a synthesis e↵ort that could provide important constraints on atmospheric models. In Venus’s mesosphere (65-85 km), visible observations of Doppler shifts in solar Fraunhofer lines, based on high-resolution spectra, have provided the only Doppler wind measurements near the cloud tops in recent years (Machado et al. 2014, 2017). We will present wind measurements based on VLT/UVES and CFHT/ESPaDOnS observations (around 70 km), wind measurements based on Akatsuki space probe data (and ESA’s Venus Express archive data) with cloud tracking methods (from 48 km till 70 km), using an improved version of a cloud tracking tool based on phase-correlation between images. The objective of this work is to help constrain the planetary atmospheric characterization, and to take a step forward in the comparative studies of terrestrial planets.
HoRSE: High Resolution Spectroscopy for Exoplanet atmospheres
Nice, France
2018 October
