Speaker: RENYU HU, JET PROPULSION LABORATORY (JPL) Title: Characterizing atmospheric chemistry in temperate exoplanets Abstract: The era of observationally characterizing temperate exoplanets and studying their atmospheric composition has begun. Hubble and JWST already have several candidate planets to study, and TESS may find another handful of temperate planets suitable for follow-up atmospheric observations. These temperate worlds are however very different from Earth – orbiting around a much cooler star, being substantially larger, or having different kinds of atmospheres. To guide observations, I couple atmospheric chemistry models with basic understandings of planetary climate and interior processes to determine the ranges ofContinue reading

Speaker: CAROLINE DORN, ETH ZURICH Title: Hidden water in magma oceans Abstract: Over the past years, there has been huge progress in our understanding of the bulk properties of sub-Neptune exoplanets. Because hot and close-in planets are abundant in the exoplanet population, phase transitions in the interiors of small, dominantly rocky planets have come into sharper focus. Here, we use coupled structural models of the interior and atmosphere of up to super-Earth-sized exoplanets to explore the effect of water partitioning into the interiors of rocky planets inside the runaway greenhouse transition and calculate the effect on the total radius ofContinue reading

Speaker: MEGAN NEWCOMBE, UNIVERSITY OF MARYLANDTitle: Efficient Degassing of Planetesimals During Melting and Differentiation: Water Delivery to Earth via Unmelted MaterialAbstract:The origin of water in the terrestrial planets is a topic of debate. Inner solar system bodies (e.g., Angrites, 4-Vesta, and the Moon) have D/H and volatile element ratios consistent with delivery of water by chondritic material, but uncertainties persist regarding the timing of that delivery, the ability of planetesimals to retain volatiles during accretion and differentiation, and the role of alternative volatile sources such as nebular ingassing and comets. We have measured water in nominally anhydrous minerals in ungroupedContinue reading

Speaker: Jacob Kegerreis, Institute for Computational Cosmology, Durham University Title: Atmospheric Erosion (and more!) by Giant Impacts onto Terrestrial Planets Abstract: Giant impacts dominate many planets' late accretion and evolution, including the Earth's, and can build, erode, or completely destroy a young atmosphere. In this talk, I'll present how we use 3D simulations to examine the erosion and other consequences of these collisions. For example, in the Moon-forming impact, only around 10% of the atmosphere would have been lost from the immediate effects of a 'canonical' impact, up to about 60% in more violent scenarios. We find a scaling lawContinue reading

Speaker: Karin Öberg, Department of Astronomy, Harvard University Title: The Chemistry of Planet Formation Abstract: Planets form in disks of dust and gas around young stars. The compositions of planets, including the hospitality to life, is fundamentally set by the composition of this dust and gas across the planet-forming disk. Recently we undertook a large ALMA project to map out the chemical content of five such disks at scales of 10s to 100s of au. We find a rich and highly unevenly distributed chemistry, manifest in 100s of molecular sub-structures including rings and gaps. I will present some of theseContinue reading

Speaker: Fabrice Gaillard, CNRS, Orleans Title: Atmophile elements in magma oceans Abstract: The process ruling the fate light volatile elements (life-forming elements, C-H-O-S-N) during the magma ocean stage are important to define since numerous geochemical observations indicate that these were delivered early on planetry systems. Here, combining experimental data and thermodynamic modelling, I will expose two axis of our research on 1- the outgassing of the magma ocean atmosphere and 2- the sequestration of some of these elements in the core. Zoom Meeting Details:  Register in advance for this webinar (registration is required for the first attendance only, you willContinue reading

Speaker: Christoph Burkhardt, Institut für Planetologie, Westfälische Wilhelms-Universität Münster Title: Mode of terrestrial planet formation and heritage of Earth's volatiles: the story from isotope anomalies in meteorites Abstract: As tracers of planetary genetics, isotope anomalies among planetary materials can provide key constraints for unraveling the Solar System’s dynamical evolution, from the collapse of the molecular cloud to the formation of the terrestrial planets. In this lecture I will show how isotope anomalies among meteorites can be used to constrain the origin of Earth’s and Mars’ building blocks, and whether pebble accretion or the classic oligarchic growth regime dominated the accretion ofContinue reading

Speaker: Oliver Shorttle, Department of Earth Sciences, University of Cambridge Title: Rocky planet atmospheres in the solar system and beyond Abstract: Planetary atmospheres potentially record a plethora of processes dating from accretion, early bombardment, and subsequent volcanic growth.  Whether for solar system planets or exoplanets, the present-day composition of atmospheres may therefore be a rich archive of information on their geological history.  In the case of warm rocky planets, those without liquid water at their surface, recycling of the volatile elements constituting the atmosphere into the planet’s interior may be or inefficient or entirely inhibited.  In this case, the atmospheresContinue reading