Chemically Anomalous, Preaccretionally Irradiated Grains in Interplanetary Dust from Comets
- 12 August 1994
- journal article
- other
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 265 (5174) , 925-929
- https://doi.org/10.1126/science.265.5174.925
Abstract
Nonstoichiometric grains with depletions of magnesium and silicon (relative to oxygen) and inclusions of iron-nickel metal and iron-rich sulfides have been identified in interplanetary dust particles from comets. These chemical anomalies accumulate in grains exposed to ionizing radiation. The grains, known as GEMS (glass with embedded metal and sulfides), were irradiated before the accretion of comets, and their inferred exposure ages, submicrometer sizes, and "amorphous" silicate structures are consistent with those of interstellar silicate grains. The measured compositional trends suggest that chemical (as well as isotopic) anomalies can be used to identify presolar interstellar components in primitive meteoritic materials.Keywords
This publication has 47 references indexed in Scilit:
- Silicate Emission Feature in the Spectrum of Comet Mueller 1993aIcarus, 1994
- Response : Vapor Deposits in the Lunar RegolithScience, 1994
- Discovery of Vapor Deposits in the Lunar RegolithScience, 1993
- Interstellar grains in meteoritesNature, 1993
- Orbital evolution of dust particles from comets and asteroidsIcarus, 1992
- Aqueous alteration on the hydrous asteroids: Results of EQ3/6 computer simulationsIcarus, 1989
- The Discovery of Dust Trails in the Orbits of Periodic CometsScience, 1986
- An overview of ion sputtering physics and practical implicationsJournal of Materials Science, 1983
- Ion implantation effects in “cosmic” dust grainsEarth and Planetary Science Letters, 1974
- Ultrathin Amorphous Coatings on Lunar Dust GrainsScience, 1972