Pluto
Pluto has a multitude of satellites and a surprisingly active surface, meaning there are many facets to study. In the lab, we focus our attention on the nitrogen-carbon monoxide-methane ternary system, particularly in the context of geological and rheological processes. In the future, we aim to perturb the system with relevant minority species to understand how they may affect the freezing/melting point of the ternary system.
Phase Behaviors of Pluto's Volatiles and the Path to the N2-CO-CH4 Equation of State
Nitrogen (N2), carbon dioxide (CO), and methane (CH4) are the most abundant supervolatile substances on Pluto, and all play a pivotal role in its geological evolution. Phase diagrams are a helpful guide to understanding surface processes occurring in regions such as Sputnik Planitia; however, there is a paucity in cryogenic data concerning these three species. This project aims to fill in these gaps by mapping out the three binary systems (N2-CO, N2-CH4) and the N2-CO-CH4 ternary system by using Raman spectroscopy to observe where phase transitions occur. This can be achieved by plotting how the centroids of a Raman peak change over time as a composition is cooled.
The laboratory results will then be combined with the CRYOCHEM 2.0 thermodynamic model (Sugata Tan, PSI) to create an equation of state that describes the interactions of the ternary system, which will be beneficial to Pluto geophysical applications.
Rheological Surface Effects
This subject is of particular interest for the future and a potential research topic for incoming graduate students.Â
The focus will be to determine whether low melting point mixed liquids can exist under the extremely low temperatures and pressures prevalent in the outer Solar System. This will be tested through a combination of theory and laboratory investigations of mixtures of known or suspected outer Solar System materials and mapping out liquidus and solidus curves in phase diagrams.
Perturbation of N2-CO system with Methane
This project focused specifically on understanding the convection of the Sputnik Planitia region and whether there was a potential for a solid phase transition in the nitrogen-carbon monoxide (N2-CO) system. Given that methane is also found in this region, it was of interest to see how the addition of the species affected the solid-solid transition.