A large donut-shaped presolar silicate from the mil 07687 carbonaceous

CHONDRITE. P. Haenecour1, C. Floss2, A. J. Brearley3, J. Y. Howe4, T. J. Zega1,5. 1Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ, USA. 2 Laboratory for Space Sciences and McDonnell for Space Sciences, Washington University in St. Louis, St. Louis, MO, USA. 3Dept. of Earth and Planetary Sciences, University of New Mexico, Albuquerque NM, USA. 4Dept. of Materials Science and Engineering, and Dept. of Chemical Engineering and Applied Chemistry, University of Toronto, Ontario, Canada. 5Dept. of Materials Science and Engineering The University of Arizona, Tucson, AZ, USA. (Email: pierre@lpl.arizona.edu).