Title:
Heavy Metal - the enigma of the largest known metal asteroid
Abstract:
Metal asteroids are some of the least explored or understood objects in the solar system. They make up only a small percentage of the bodies in the asteroid belt, which are mostly rocky. Their inferred densities and reflectivity suggest they are heavy and metallic, and are sometimes thought to be fragments of planetary cores - the only known “factory” in the universe that can manufacture big chunks of metal. However, their actual chemical composition has never been confirmed, as none of them was observed and measured up close.
(16) Psyche is the largest known metallic asteroid, with a radius of 226 km. The NASA Psyche mission, scheduled to launch in 2022, would be the first journey to a metallic world, and is tasked with revealing whether Psyche is an exposed planetary core. One of the key lines of inquiry iis determining whether Psyche is magnetized - much like magnets on Earth, minerals making up Psyche could have been magnetized by a past planetary magnetic field it may have one carried.
The detection of remanent magnetization would be the first ever discovery of a magnetized asteroid, and may also lead to the first observation of an asteroid magnetosphere. While the known magnetospheres of large planetary bodies have been studied extensively by spacecraft, a magnetized asteroid likely presents a type of magnetosphere not yet explored. Predicting the possible types of interaction region is critical for mission planning and science operations.
In this seminar, I will describe the range of known interaction regions between planetary bodies and the solar wind, and what we can learn from plasma and magnetic field measurements from orbit about their interiors. We analyze the feasibility of plasma structures such as shocks, magnetopause current layers, particle trapping, and waves around these bodies using hybrid plasma simulations and particle tracing. We compare the predicted scenarios to observations of the magnetospheres of Mercury and Ganymede.
Bio:
Dr. Rona Oran is a research scientist at MIT and an expert in computational plasma physics and space exploration. She is a member of the team planning NASA’s mission to asteroid Psyche, to be launched in 2022. Dr. Oran develops advanced computational tools, including magnetohydrodynamics, hybrid, and particle codes to address fundamental questions about the solar system.
She harnesses the powerful computational tools of space physics to address open questions in planetary science and exploration, and is an avid supporter or cross-disciplinary collaborations that can carve new paths for discovery. Her contributions include constraining the magnetization and differentiation histories of asteroids, eliminating impact plasmas as the source of lunar magnetic anomalies, and showing that the conclusions of stellar evolution theory, stellar wind modeling, and meteorite paleomagnetism all tell a similar story about our solar system. She is part of an international team defining the current knowledge in lunar science, co-authoring the book New Views of the Moon II. On the space exploration front, Dr. Oran develops scientific analysis and data pipelines for the magnetometer investigation for the NASA Psyche mission, in preparation for detecting and characterising its possible magnetic field, which would be the first detection of a magnetized asteroid.
Dr. Oran earned her Ph.D. at the University of Michigan’s Center for Space Environment Modeling and her post-doctoral training at the Department of Earth, Atmospheric, and Planetary Sciences at MIT. Dr Oran also serves as the Vice President of the Massachusetts Chapter of the Association for Women in Science and the co-chair of the Mentoring Program.