Identification of isotopically primitive interplanetary dust particles: A NanoSIMS isotopic imaging study

Abstract

We have carried out a comprehensive survey of the isotopic compositions (H, B, C, N, O, S) of a suite of interplanetary dust particles (IDPs), including both cluster and individual particles. Isotopic imaging with the NanoSIMS shows the presence of numerous discrete hotspots that are strongly enriched in 15 Based on their N isotopic compositions, the IDPs studied here can be divided into two groups. One group is characterized as being "isotopically primitive" and consists of those IDPs that have anomalous bulk N isotopic compositions. These particles typically also contain numerous 15 N-rich hotspots, occasional C isotopic anomalies, and abundant presolar silicate grains. In contrast, the other "isotopically normal" IDPs have normal bulk N isotopic compositions and, although some contain 15 N-rich hotspots, none exhibit C isotopic anomalies and none contain presolar silicate or oxide grains. Thus, isotopically interesting IDPs can be identified and selected on the basis of their N isotopic compositions for further study. However, isotopes. This may be due to different effects of secondary processing on the isotopic systems involved.3

Cometary Isotopic Measurements

“…The 14 N/ 15 N values derived from the HCN emission at sub-millimetre range (323 ± 46, Jewitt et al 1997;330 ± 98 ) and other comets ), in NH 3 from NH 2 observations Shinnaka et al 2014b), in dust particles of comet 81P/Wild 2 collected by the Stardust mission (McKeegan et al 2006), in interplanetary dust particles IDPs (Floss et al 2006), and in the insoluble organic matter (IOM) in carbonaceous meteorites (Busemann et al 2006). So-called hotspots are regions that present strong isotopic enrichments relative to the surrounding material.…”

Cometary Isotopic Measurements

“…Subsequent observations of a dozen comets of various origins lead to 14 N/ 15 N = 147.8 ± 5.7 from CN ). The discrepancy between CN and HCN, a presumed parent, was eventually solved with the quasi simultaneous sub-millimeter and optical observations of HCN and CN in comet 17P/Holmes performed a couple of days after its huge and bright outburst in (Arpigny et al 2003;) and other comets ), in NH 3 from NH 2 observations Shinnaka et al 2014b), in dust particles of comet 81P/Wild 2 collected by the Stardust mission (McKeegan et al 2006), in interplanetary dust particles IDPs (Floss et al 2006), and in the insoluble organic matter (IOM) in carbonaceous meteorites (Busemann et al 2006). So-called hotspots are regions that present strong isotopic enrichments relative to the surrounding material.…”

Dust in the Solar System: Properties and Origins

“…Second, CP-IDPs have C abundances that are more similar to comets than meteorites [51]. Third, CP-IDPs have high abundances of presolar grains and molecular cloud material [68][69][70]. Finally, CP-IDPs have experienced minimal parent body alteration, as shown by highly unequilibrated and anhydrous mineralogy.…”