Identification of an 84Sr-depleted carrier in primitive meteorites and implications for thermal processing in the solar protoplanetary disk
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Identification of an 84Sr-depleted carrier in primitive meteorites and implications for thermal processing in the solar protoplanetary disk. / Paton, Chad; Schiller, Martin; Bizzarro, Martin.
I: The Astrophysical Journal Letters, Bind 763, Nr. 2, L40, 2013.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - Identification of an 84Sr-depleted carrier in primitive meteorites and implications for thermal processing in the solar protoplanetary disk
AU - Paton, Chad
AU - Schiller, Martin
AU - Bizzarro, Martin
PY - 2013
Y1 - 2013
N2 - The existence of correlated nucleosynthetic heterogeneities in solar system reservoirs is now well demonstrated for numerous nuclides. However, it has proven difficult to discriminate between the two disparate processes that can explain such correlated variability: incomplete mixing of presolar material or secondary processing of a well-mixed disk. Using stepwise acid-leaching of the Ivuna CI-chondrite, we show that unlike other nuclides such as Cr and Ti, Sr-isotope variability is the result of a carrier depleted in Sr. The carrier is most likely presolar SiC, which is known to have both high Sr-concentrations relative to solar abundances and extremely depleted Sr compositions. Thus, variability in Sr in meteorites and their components can be attributed to varying contributions from presolar SiC. The observed Sr excesses in calcium-aluminum refractory inclusions (CAIs) suggest their formation from an SiC-free gaseous reservoir, whereas the Sr depletions present in differentiated meteorites require their formation from material with an increased concentration of SiC relative to CI chondrites. The presence of a positive correlation between Sr and Cr, despite being hosted in carriers of negative and positive anomalies, respectively, is not compatible with incomplete mixing of presolar material but instead suggests that the solar system's nucleosynthetic heterogeneity reflects selective thermal processing of dust. Based on vaporization experiments of SiC under nebular conditions, the lack of SiC material in the CAI-forming gas inferred from our data requires that the duration of thermal processing of dust resulting in the vaporization of CAI precursors was extremely short-lived, possibly lasting only hours to days.
AB - The existence of correlated nucleosynthetic heterogeneities in solar system reservoirs is now well demonstrated for numerous nuclides. However, it has proven difficult to discriminate between the two disparate processes that can explain such correlated variability: incomplete mixing of presolar material or secondary processing of a well-mixed disk. Using stepwise acid-leaching of the Ivuna CI-chondrite, we show that unlike other nuclides such as Cr and Ti, Sr-isotope variability is the result of a carrier depleted in Sr. The carrier is most likely presolar SiC, which is known to have both high Sr-concentrations relative to solar abundances and extremely depleted Sr compositions. Thus, variability in Sr in meteorites and their components can be attributed to varying contributions from presolar SiC. The observed Sr excesses in calcium-aluminum refractory inclusions (CAIs) suggest their formation from an SiC-free gaseous reservoir, whereas the Sr depletions present in differentiated meteorites require their formation from material with an increased concentration of SiC relative to CI chondrites. The presence of a positive correlation between Sr and Cr, despite being hosted in carriers of negative and positive anomalies, respectively, is not compatible with incomplete mixing of presolar material but instead suggests that the solar system's nucleosynthetic heterogeneity reflects selective thermal processing of dust. Based on vaporization experiments of SiC under nebular conditions, the lack of SiC material in the CAI-forming gas inferred from our data requires that the duration of thermal processing of dust resulting in the vaporization of CAI precursors was extremely short-lived, possibly lasting only hours to days.
U2 - 10.1088/2041-8205/763/2/L40
DO - 10.1088/2041-8205/763/2/L40
M3 - Journal article
AN - SCOPUS:84873356531
VL - 763
JO - The Astrophysical Journal Letters
JF - The Astrophysical Journal Letters
SN - 2041-8205
IS - 2
M1 - L40
ER -
ID: 45193034