Thesis Proposal Presentation by Jessica Blagen on February 7th
Space Studies master’s student, Jessica Blagen, will give her thesis proposal presentation as follows.
When: Tuesday, February 7th at 4:00 p.m.
Where: Ryan Hall, Room 111
Title: Testing the Gefion family as a possible parent body for the L-chondrite meteorites.
The ordinary chondrites, at around 80%, are the most abundant types of meteorites falling to Earth. Based on Antarctic meteorite collections, this prevalence has been maintained for at least the past million years. The ordinary chondrites are subdivided into three groups based on the ratio of metallic iron to oxidized iron. The L-chondrite meteorites are intermediate between the H- and LL-chondrites in both abundance of NiFe metal, mafic mineral composition, and redox state, and L-chondrites are the most abundant ordinary chondrite falls, comprising ~38% of all meteorite falls.
Identifying the parent bodies for the ordinary chondrites has been an important goal of asteroid science for more than thirty years. Linking meteorites to an asteroid, or asteroid family, makes it possible to pinpoint particular isotopic and mineralogical compositions to a specific location within the asteroid belt. This allows for a more robust understanding of the thermal and compositional gradients present in the solar nebula. An unambiguous determination of a genetic relationship will most likely require a sample return mission. However, probable or plausible parent bodies can be identified based on two main criteria. A plausible meteorite parent body will be an asteroid that either has a surface mineralogy compatible with that of the L-chondrite meteorites, or which is in an orbital location that can provide quantitative yields of the relevant amount of meteoroids to the Earth. A probable parent body will meet both criteria.
It has recently been proposed by Nesvorny et al. (2009) and coworkers, based on dynamical models, that the Gefion Family of asteroids may be the source of the L-chondrite meteorites. This study uses infrared spectroscopy data gathered using the NASA Infrared Telescope Facility to determine the mineralogy of two asteroids of the Gefion Family. The CCD spectra of 132 core members of the Gefion family taken from the SMASS database indicate that S-type asteroids, of which the L-chondrites are a subset, dominate the Gefion Family. The results of this study will provide mineralogical characterization of two Gefion Family members, testing the hypothesis that this family is a possible source of the L-chondrite meteorites.