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Abstract: Titan stands out amongst satellites in our solar system as a strangely Earth-like world, including an active precipitation cycle with liquid present at the surface. It is also noteworthy for the abundant organics coating the surface, including the equatorial dunes. Titan’s thick, nitrogen-dominated atmosphere is a critical driver of the present-day state of this planetary system, stabilizing liquid hydrocarbons, and producing organics via photochemistry. In this presentation, I will discuss the origin of Titan’s atmospheric volatiles, including nitrogen, methane, and argon. I will review evidence that supports an atmospheric contribution of as much as 50% from complex organic material similar to insoluble organic matter found in chondrites, present experimental work to test this hypothesis, and discuss broader implications for Titan’s interior and habitability.

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Abstract: Direct imaging observations of young planetary systems provide a context for the formation and evolution of our solar system.   In this talk, I describe our effort to directly image planet-forming disks and protoplanets with the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) project on the Subaru telescope.   Our work provides a new look at the disk around solar-mass star LkCa 15 and a reevaluation of its previously proposed protoplanets.   On the other hand, SCExAO data identify evidence for jovian planet formation at a wide separation around the more massive star AB Aurigae: possible evidence for planet formation by disk instability.  Finally, I chart the near-term path forward for studying planet formation with SCExAO.   SCExAO’s new wavefront sensor upgrade makes accessible dozens of structured protoplanetary disks around optically-faint, typically low-mass stars.   Our program over the next few years will assess the likely birth locations of jovian protoplanets in these disks and inform the mechanisms by which these planets may be forming.

The contact person for 2022-2023 series is Munazza Alam. Email: malam at carnegiescience.edu. 

Full schedule here.

TEST content here. 

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Abstract: Rotating tanks are a powerful teaching tool from the elementary through graduate school levels. They are ideal for demonstrating the basic fluid dynamics that underlie weather, climate, ocean circulation, and planetary and stellar interior fluid motions. Over the past 5 years, we have developed a series of do-it-yourself (DIY) kits for building and carrying out desktop rotating tank experiments. In this talk, Dr. Aurnou will go over the basic concepts and then carry out a set of desktop experiments with participants taking active part in these hands-on science activities. With the interesting weather we have been having the last few weeks, winter-time instabilities of the polar jet stream will be the main problem we hone in on.

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Title: "Determining C/N/O Abundances in Protoplanetary Disks via Observations of Molecular Emission"

Abstract: Characterizing the chemical composition of planet-forming materials in protoplanetary disks around young stars is an important step in interpreting the formation and evolution histories of planets. While molecular emission from protoplanetary disk gases is sensitive to various physical and chemical disk properties, it only provides a partial view of the complete chemical contents of the disk. Using physical/chemical disk modeling we attempt to connect molecular line observations of protoplanetary disks to the underlying chemical abundances in disk materials. In this talk, I will present modeling results and submillimeter molecular line observations focused on major carriers of carbon, nitrogen, and oxygen in protoplanetary disks. I will also discuss the potential for deriving C, N, and O abundances from telescope observations of bright, observable molecular species.

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Title: "Clinopyroxene-melt Trace Element Partitioning in Fe-rich Basaltic Systems"

Abstract: Trace element partitioning in Fe-rich basaltic systems is understudied but is important for understanding petrogenesis of Fe-rich magmatic bodies. Clinopyroxenes are a major host of incompatible elements in planetary interiors, thus the study of their incompatible trace element inventories can yield important information on the melting and fractionation processes during igneous petrogenesis. This work explores trace element partitioning in clinopyroxenes with variable Fe and Al content at 1 and 2 GPa and utilizes the results to create predictive lattice strain models. These models can be applied to understand the evolution of natural Fe-rich magmatic systems on Earth and in the Solar System.

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Abstract: The recent launch of JWST promises detailed characterization of hot gaseous exoplanets through emission and transmission spectroscopy observations. In this talk, I will discuss the current understanding of the atmospheric circulation of hot gaseous exoplanets ("hot Jupiters’’) as determined from interpreting astronomical observation with a combination of analytic theory and general circulation modeling. I will introduce the hottest gaseous exoplanets, "ultra-hot Jupiters,’’ as a novel extreme class of exoplanet characterized by thermal dissociation of molecules and patchy mineral cloud coverage. I will describe the current efforts to characterize the atmospheres of hot and ultra-hot Jupiters with JWST, along with potential avenues for further exploration. 

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Abstract: Earth’s core-mantle boundary features a complex landscape of multi-scale structures whose heterogeneous compositions and physical properties likely influence key phenomena in Earth’s interior. Interdisciplinary advances in the past decade have shown that mountain-scale structures discovered at roots of mantle plumes may be strongly enriched in solid FeO, a material exhibiting various unique but poorly constrained properties at deep Earth conditions.

Here, Dr. Dobrosavljevic will share his recent experimental results on the melting of FeO, as well as theoretical work on the material’s insulator-metal transition at these extreme conditions. These findings suggest the presence of solid FeO-rich regions at Earth’s mantle base can explain independent observations from multiple geophysical probes.

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Abstract: I will be discussing my previous search for nearby companion planets to hot Jupiters, the calculation of their occurrence rates, and the implications of the formation pathways of these systems. I will also bookend the life of hot Jupiters with a discussion on the orbital decay of hot Jupiters into their host stars and the new possibilities emerging to detect this phenomenon. Time permitting, I will also present my efforts to identify and statistically validate the best-in-class targets for atmospheric characterization with JWST and future missions.

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Abstract: Presolar stardust grains are tiny and rare components of meteorites. They were produced in the winds and explosions of ancient dying stars and were part of the molecular cloud from which the Solar System formed. By analyzing their compositions, we can learn how stars synthetized elements and their isotopes. Studying presolar grains is also the only known way of directly examining some of the building blocks of the Solar System in the laboratory. They can tell us what type of material and which processes ultimately formed the Sun and planets. In this talk, we will explore a new dataset of presolar grain abundances and multi-element isotopic compositions collected with the Carnegie NanoSIMS. The samples include previously unstudied meteorites and material recently returned from asteroid Ryugu by the Hayabusa2 spacecraft. We will examine what these presolar grains can tell us about their origin and the early evolution of the solar system.