TY - JOUR
T1 - A chondrule-like object captured by space-exposed aerogel on the international space station
AU - Noguchi, T.
AU - Nakamura, T.
AU - Ushikubo, T.
AU - Kita, N. T.
AU - Valley, J. W.
AU - Yamanaka, R.
AU - Kimoto, Y.
AU - Kitazawa, Y.
N1 - Funding Information:
We appreciate IHI Aerospace Co. Ltd., Advanced Engineering Services Co. Ltd., and Nissan Arc Co. Ltd. for supporting the optical inspection of the silica aerogel tiles. We thank H. Nagahara and H. Yoshida for permission to use FE-SEM and EPMA at University of Tokyo. We thank K. Shimada, K. Sakamoto and R. Okazaki, for making it possible for us to perform FE-EPMA analysis at Kyushu University. We appreciate M. Kimura's comments on opaque mineralogy of chondrules. Constructive comments by two anonymous reviewers helped to improve our manuscript considerably. This work is supported by NASA grants NNX07AI46G and NNX09AC30G (N.K.) and by a Grant-in-aid of the Japan Ministry of Education, Culture, Sports, Science and Technology ( 17340157 ) to T. Noguchi. WiscSIMS is supported partly by NSF (EAR03-19230 and EAR07-44079). The machine fee was supported by a Grant-in-aid of the Japan Ministry of Education, Culture, Sports, Science and Technology ( 19104012 ) to T. Nakamura.
PY - 2011/9/15
Y1 - 2011/9/15
N2 - Here we report on the mineralogy, petrography, and oxygen-isotope compositions of a micrometeoroid captured on the international space station. This micrometeoroid has the texture of a porphyritic olivine chondrule. Because hydrated phases were not identified in the micrometeoroid and because Ni-rich sulfide in it does not show exsolution of pentlandite on the TEM scale, the micrometeoroid probably escaped low temperature events such as aqueous alteration on its parent body. However, the mean value and standard deviation of Cr2O3 wt.% in olivine in the micrometeoroid suggest that the micrometeoroid experienced weak thermal metamorphism. Oxygen isotope ratios of pyroxene and olivine in the micrometeoroid are similar to those of chondrule-like objects in comet 81P/Wild2 and coarse-grained crystalline micrometeorites as well as those in chondrules in major types of carbonaceous chondrites. These data suggest that the micrometeoroid is a fragment of a chondrule-like object that was derived from a primitive parent body that experienced thermal metamorphism.
AB - Here we report on the mineralogy, petrography, and oxygen-isotope compositions of a micrometeoroid captured on the international space station. This micrometeoroid has the texture of a porphyritic olivine chondrule. Because hydrated phases were not identified in the micrometeoroid and because Ni-rich sulfide in it does not show exsolution of pentlandite on the TEM scale, the micrometeoroid probably escaped low temperature events such as aqueous alteration on its parent body. However, the mean value and standard deviation of Cr2O3 wt.% in olivine in the micrometeoroid suggest that the micrometeoroid experienced weak thermal metamorphism. Oxygen isotope ratios of pyroxene and olivine in the micrometeoroid are similar to those of chondrule-like objects in comet 81P/Wild2 and coarse-grained crystalline micrometeorites as well as those in chondrules in major types of carbonaceous chondrites. These data suggest that the micrometeoroid is a fragment of a chondrule-like object that was derived from a primitive parent body that experienced thermal metamorphism.
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U2 - 10.1016/j.epsl.2011.06.032
DO - 10.1016/j.epsl.2011.06.032
M3 - Article
AN - SCOPUS:80052803847
SN - 0012-821X
VL - 309
SP - 198
EP - 206
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 3-4
ER -