Isotopic Compositions of Cometary Matter Returned by Stardust
2006
McKeegan, Kevin D. | Aléon, Jerome | Bradley, John | Brownlee, Donald | Busemann, Henner | Butterworth, Anna | Chaussidon, Marc | Fallon, Stewart | Floss, Christine | Gilmour, Jamie | Gounelle, Matthieu | Graham, Giles | Guan, Yunbin | Heck, Philipp R. | Hoppe, Peter | Hutcheon, Ian D. | Huth, Joachim | Ishii, Hope | Ito, Motoo | Jacobsen, Stein B. | Kearsley, Anton | Leshin, Laurie A. | Liu, Ming-Chang | Lyon, Ian | Marhas, Kuljeet | Marty, Bernard | Matrajt, Graciela | Meibom, Anders | Messenger, Scott | Mostefaoui, Smail | Mukhopadhyay, Sujoy | Nakamura-Messenger, Keiko | Nittler, Larry | Palma, Russ | Pepin, Robert O. | Papanastassiou, Dimitri A. | Robert, François | Schlutter, Dennis | Snead, Christopher J. | Stadermann, Frank J. | Stroud, Rhonda | Tsou, Peter | Westphal, A. J. | Young, Edward D. | Ziegler, Karen | Zimmermann, Laurent | Zinner, Ernst
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.
显示更多 [+] 显示较少 [-]