Condensed Matter Physics Seminar
“Condensed Matter from Space: Thermal Properties of CM2 Meteorites”
Dr. Cyril P. Opeil
Physics Department
Boston College
Abstract: Measurement of the low-temperature thermodynamic and physical properties of meteorites provides fundamental data for the study and understanding of asteroids and other small bodies. Of particular interest are the CM carbonaceous chondrites, which represent a class of primitive meteorites that record substantial chemical information concerning the evolution of the volatile-rich materials in the early solar system. Most CM chondrites contain both anhydrous minerals such as olivine and pyroxene, along with abundant hydrous phyllosilicates contained in the meteorite matrix interspersed between the chondrules. We have measured the thermal conductivity, heat capacity and thermal expansion of five CM carbonaceous chondrites (Murchison, Murray, Cold Bokkeveld, NWA 7309, Jbilet Winselwan) at low temperatures (5-300 K) that span the range of possible surface temperatures in the asteroid belt. The thermal expansion measurements show a substantial and unexpected decrease in CM volume as temperature decreases from 230 - 210 K followed by a gradual contraction below 210 K. Such transitions are not typical for other CV or CO carbonaceous chondrites. Thermal diffusivity and thermal inertia as a function of temperature are calculated from measurements of density, thermal conductivity and heat capacity. Our thermal diffusivity results compare well with previous estimates for similar meteorites, where conductivity was derived from diffusivity measurements and modeled heat capacities; our new values are of higher precision and cover a wider range of temperatures.
Tuesday, November 19, 2019
2:00 PM
Gant South Building, Room GS-119
For more information, contact: Anna Huang at Anna.huang@uconn.edu