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A NanoSIMS and Auger Nanoprobe investigation of an isotopically primitive interplanetary dust particle from the 55P/Tempel‐Tuttle targeted stratospheric dust collector
Author(s) -
FLOSS Christine,
STADERMANN Frank J.,
MERTZ Aaron F.,
BERNATOWICZ Thomas J.
Publication year - 2010
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2010.01126.x
Subject(s) - meteorite , interplanetary dust cloud , astrobiology , presolar grains , chondrite , asymptotic giant branch , comet , geology , silicate , geochemistry , astrophysics , astronomy , solar system , physics , stars
Abstract– An IDP nicknamed Andric, from a stratospheric dust collector targeted to collect dust from comet 55P/Tempel‐Tuttle, contains five distinct presolar silicate and/or oxide grains in 14 ultramicrotome slices analyzed, for an estimated abundance of approximately 700 ppm in this IDP. Three of the grains are 17 O‐enriched and probably formed in low‐mass red giant or asymptotic giant branch (AGB) stars; the other two grains exhibit 18 O enrichments and may have a supernova origin. Carbon and N isotopic analyses show that Andric also exhibits significant variations in its N isotopic composition, with numerous discrete 15 N‐rich hotspots and more diffuse regions that are also isotopically anomalous. Three 15 N‐rich hotspots also have statistically significant 13 C enrichments. Auger elemental analysis shows that these isotopically anomalous areas consist largely of carbonaceous matter and that the anomalies may be hosted by a variety of components. In addition, there is evidence for dilution of the isotopically heavy components with an isotopically normal endmember; this may have occurred either as a result of extraterrestrial alteration or during atmospheric entry. Isotopically primitive IDPs such as Andric share many characteristics with primitive meteorites such as the CR chondrites, which also contain isotopically anomalous carbonaceous matter and abundant presolar silicate and oxide grains. Although comets are one likely source for the origin of primitive IDPs, the presence of similar characteristics in meteorites thought to come from the asteroid belt suggests that other origins are also possible. Indeed the distinction between cometary and asteroidal sources is somewhat blurred by recent observations of icy comet‐like planetesimals in the outer asteroid belt.