20 November, 2024:
The Diverse Rocky Materials that Formed Comets
Recorded Lecture:
Stardust, the first sample return mission to a primitive body, collected thousands of well-preserved 1-60 µm solid particles from an active 4 km comet. Nearly all the comet silicate materials >2µm formed at high temperature and most are chondrule fragments that could not have formed in the same environment where the cometary volatiles condensed. A fundamental and distinctive property of the comet dust is that it is an unequilibrated weak carbon-rich aggregate of anhydrous rocky nebular materials that were previously packed in ice but do not contain significant amounts of secondary minerals such as phyllosilicates, carbonates and phosphates that are abundant in carbon rich meteorites and samples returned from primitive asteroids. The sampled comet, as well as porous interplanetary dust particles of probable cometary origin, preserve primary nebular solids such as chondrule and CAI fragments as well as presolar grains probably because most comets formed small, far from the Sun, and their interiors never had the internal pressure and temperature needed to melt ice and produce extensive aqueous alteration.
Lecture by: Don Brownlee, University of Washington
Don Brownlee is a professor of astronomy at the University of Washington. He has spent his entire career collecting and analyzing "meteoritic materials” from space, the stratosphere, polar regions and the abyssal sediments. He was the Principle Investigator of the NASA Stardust mission that returned the only laboratory samples that are known to be from a comet that formed at the edge of the solar system. He received the Meteoritical Society Leonard Medal in 1996.
29 APRIL, 2024:
Achondrite Meteorites: Messengers of Early Planetary Accretion and Evolution
Recorded Lecture:
Primitive and basaltic achondrite meteorites provide insights into planetesimal formation and differentiation processes. The increasing number and diversity of achondrite meteorites contribute to a better understanding of chemical reservoirs, accretion timescales, and dynamical evolution of planetary bodies throughout the Solar System. This presentation will give an overview of their petrological significance and comparative chronology in addressing several key questions about the formation of the protoplanetary disk and planets.
Lecture by: Audrey Bouvier, University of Bayreuth
Audrey Bouvier is a cosmochemist and professor at the Bavarian Research Institute of Experimental Geochemistry and Geophysics at the University of Bayreuth. In her research, she principally uses petrological and metal isotope studies of meteorites and returned samples to assess the origin, evolution, and impact histories of planetary materials and their parent bodies. She was a member of the JAXA Hayabusa2 initial analysis chemistry team of Ryugu, and is currently an ESA-appointed member of the Mars Sample Return Campaign Science Group and of the Science Strategy Team on Early Solar System Evolution and Sample Analysis Working Team of the Martian Moons eXploration (MMX) JAXA mission. She received the Nier Prize (2013) and is a Fellow (2018) of the Meteoritical Society.
20 February, 2024:
Mars Sample Return: Why Martian Meteorites and Rover Missions Are Not Enough
Recorded Lecture:
Mars Sample Return is among the most challenging (and costly) mission concepts ever attempted. This presentation will consider why the almost 200 martian meteorites now available are not sufficient to address critical questions about Mars geologic (and possibly biologic) history, and what we might learn from returned samples.
Lecture by: Dr. Harry "Hap" Y. McSween, University of Tennessee
Hap McSween is a petrologist/cosmochemist who has been involved in Mars research since he was one of the original proponents of the idea that we have martian meteorites. He has been involved in multiple Mars spacecraft missions, as well as investigations of many other meteorite types.
14 November, 2023:
IIE Iron Meteorites as Ordinary Chondrites: Surprising Insights into the Chemical Evolution of the Solar Nebula
Recorded Lecture:
Even though the IIE meteorites are irons, a few contain chondrule-bearing clasts. These clasts and the metal fraction have chemical and isotopic compositions that show that they constitute the fourth major ordinary-chondrite group. Considered collectively, these four groups provide insights into the nature of the chemical fractionations that occurred in the solar nebula.
Lecture by: Dr. Alan E. Rubin, UCLA
Alan Rubin received a B.S. in Astronomy from the University of Illinois, Urbana in 1974, after which he worked part-time at the Adler Planetarium in Chicago. He obtained an M.S. in Geological Sciences from the University of Illinois, Chicago in 1979, and a Ph.D. in Geology from the University of New Mexico in 1982. Ed Olsen was his M.S. advisor and Klaus Keil his Ph.D. advisor. While at New Mexico, Rubin also worked with Jeff Taylor and Ed Scott. Rubin was a post-doctoral fellow at the Smithsonian from 1982-1983 under the supervision of Roy Clarke. He went on to UCLA where he joined John Wasson’s group. Rubin has published about 220 research papers on all varieties of meteorites, as well as 50 popular-level articles and three non-fiction books. He notes that, as a garnet, his eponymous mineral is semi-precious.