Isotopic Compositions of Cometary Matter Returned by Stardust
Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single 17O-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is 16O-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion.
Physics and Astronomy
K. D. McKeegan, J. Aléon, C. M. O’D. Alexander, J. Bradley, D. Brownlee, P. Burnard, H. Busemann, A. Butterworth, M. Chaussidon, A. Davis, C. Floss, J. Gilmour, M. Gounelle, G. Graham, Y. Guan, P. Heck, C. Hohenberg, P. Hoppe, I. D. Hutcheon, J. Huth, H. Ishii, M. Ito, S. Jacobsen, L. A. Leshin, I. Lyon, K. Marhas, B. Marty, G. Matrajt, A. Meibom, A. Meshik, S. Messenger, S. Mostefaoui, K. Nakamura-Messenger, L. Nittler, R. Palma, M. Pellin, R. O. Pepin, R. Pik, D. A. Papanastassiou, F. Robert, M. R. Savina, D. Schlutter, C. J. Snead, F. J. Stadermann, R. Stroud, P. Tsou, A. Westphal, E. D. Young, K. Ziegler, L. Zimmermann, E. Zinner, 2006. Isotopic Compositions of Cometary Matter Returned by Stardust. Science 314, 1724-1728.
Publisher's Copyright and Source
Copyright © 2006 American Association for the Advancement of Science. Article published by the American Association for the Advancement of Science in Science, volume 314, issue number 5806, December 15, 2006, pages 1724-1728. Available online: http://doi.org/10.1126/science.1135992.