October 27th Brown Bag seminar by Rachel Roberts
The fall semester Brown Bag Seminar Series features graduate students providing presentations on their current research and recent internships. This series of presentations is held in the Space Studies Library at 12:30 PM. Lunch will be served.
On October 27th, Rachel Roberts will present her talk about her graduate work entitled ” Testing the Gefion Dynamical Asteroid Family as a Possible Source of the L-Chondrites.”
About the Presentation: Identification of main-belt parent bodies of the most common meteorites, the ordinary (H, L & LL) chondrites, has been a priority for asteroid science for more than four decades. Linking a class of meteorites to a particular asteroidal parent body allows the detailed temporal and physical information from the meteorites to be placed into an early solar system spatial context, constraining models of solar nebula and early solar system evolution. Asteroid families are fragments of collisionally disrupted bodies which follow similar orbits. Recent dynamical models proposed that the Gefion asteroid family is the source of the L-chondrites, the most abundant ingle type of meteorite. A large portion of L-chondrites record a strong shock event at about 480 million years ago and very abundant fossil L-chondrites are found in terrestrial geologic deposits formed at that time. Meteoritic evidence indicates that all the L-chondrites originated from a single original parent body. The L-chondrite parent body suffered a catastrophic collision at ~480 Myr producing an asteroid family and a shower of L-chondrite meteoroids onto the Earth. Since the L-chondrite parent body was undifferentiated, all the fragments that body would be L-chondrite material. Meteorite types are distinguished based on the abundances and compositions of their constituent minerals; therefore, mineralogical characterizations are required to test the hypothesis that the Gefion family is composed of L-chondrite objects. Confirming a link between L-chondrites and the Gefion family would identify the source of ~35% of the meteorites and would establish a formation age for the Gefion family that would constrain models of asteroid orbital and collisional evolution. If the Gefion family is not composed primarily of L-chondrite material, that would suggest that the dynamical models need to be reexamined and that other families should be investigated as the L-chondrite source.
About the presenter: Rachel Roberts earned her B.S. degree in Mathematics at Oregon State University. She is a GRA for Dr. Gaffey and is working on her thesis for her Master’s degree. Her interests include asteroid-meteorite connection and evolution, Early Solar system formation, asteroid composition/mineralogy, and planetary geology.