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Constraints on the formation environment of two chondrule‐like igneous particles from comet 81P/Wild 2
Author(s) -
Gainsforth Zack,
Butterworth Anna L.,
Stodolna Julien,
Westphal Andrew J.,
Huss Gary R.,
Nagashima Kazu,
Ogliore Ryan,
Brownlee Donald E.,
Joswiak David,
Tyliszczak Tolek,
Simionovici Alexandre S.
Publication year - 2015
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/maps.12445
Subject(s) - chondrule , meteorite , comet , liquidus , chondrite , astrobiology , geology , igneous rock , interplanetary dust cloud , geochemistry , mineralogy , solar system , chemistry , physics , phase (matter) , organic chemistry
Using chemical and petrologic evidence and modeling, we deduce that two chondrule‐like particles named Iris and Callie, from Stardust cometary track C2052,12,74, formed in an environment very similar to that seen for type II chondrules in meteorites. Iris was heated near liquidus, equilibrated, and cooled at ≤100 °C h ‐1 and within ≈2 log units of the IW buffer with a high partial pressure of Na such as would be present with dust enrichments of ≈10 3 . There was no detectable metamorphic, nebular, or aqueous alteration. In previous work, Ogliore et al. (2012) reported that Iris formed late, >3 Myr after CAIs, assuming 26 Al was homogenously distributed, and was rich in heavy oxygen. Iris may be similar to assemblages found only in interplanetary dust particles and Stardust cometary samples called Kool particles. Callie is chemically and isotopically very similar, but not identical to Iris.