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Investigation for the Ingredients of Life in Asteroids

Presentation #122.01 in the session “Laboratory Astrophysics Division (LAD): Sample Return & Aromatic/Exotic Molecules in Space”.

Published onJun 18, 2021
Investigation for the Ingredients of Life in Asteroids

Several successful flyby and sample return missions to the small bodies in our Solar System have made exciting discoveries. The sample return missions has transformed our understanding of asteroids and comets via sophisticated instrumentation available in terrestrial laboratories. The laboratory analyses unveiled the geologic history of these bodies in exquisite detail and has the ability to assess the potential for these bodies to harbor life’s essential ingredients. A small amount of dust collected by the Japanese spacecraft Hayabusa from the surface of the S-Type asteroid 25143 Itokawa provided extraordinary information of how rocky, small bodies form, how they can evolve under hydrothermal conditions, and what happens after they get shattered in a catastrophic collision. Itokawa-like asteroids are the source of the most common kind of meteorites found on Earth namely the ordinary chondrite meteorites. Extensive petrologic, mineralogic and isotopic studies on Itokawa regolith minerals and ordinary chondrite meteorites have shown great similarities. Our study on the water contained within the silicate minerals show how planetary embryos and planets formed in the inner solar system from ordinary chondrite materials were likely formed wet. This result led us to explore methods by which protons in the solar nebula could be ionized and subsequently implanted within silicate minerals in the matter of days or years. We have collected massive amounts of regolith rocks from two asteroids, Bennu and Ryugu that belong to the Cb class of asteroids, analogous to carbonaceous chondrite meteorites. These asteroids are rich in water-ice and organic materials. In order to prepare for analyses of these samples, we have investigated cosmic dust particles on the micron-to-millimeter scale that originate from extraterrestrial bodies, pass through Earth’s atmosphere, and get collected in Antarctic ice. Investigating the largest fine-grained, unmelted micrometeorite TAM19B-7 found to date, we inferred that it has oxygen isotopic composition that closely resemble the materials from an ultra-hydrated carbonaceous chondrite (CM or CR) group. In spite of being this hydrated, it contains disordered carbon, graphene, carbonates and carbon-anomalous organic coatings of interstellar origin. I will talk briefly about these missions to asteroids, the work that was done or is ongoing with Itokawa samples at Arizona State University, and how my team is preparing for the analyses of samples from Bennu and Ryugu.

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