H, C and N isotopic compositions of HAYABUSA Category 3
organic samples.
M. Ito1, M. Uesugi2, H. Naraoka3, H. Yabuta4, F. Kitajima3, H.
Mita5, Y. Takano1 Y. Karouji2, T. Yada2, Y. Ishibashi2, T.
Okada2 and M. Abe2. 1JAMSTEC. motoo@jamstec.go.jp.
2
JAXA/ISAS. 3Kyushu University. 4Osaka University. 5Fukuoka
Inst. Tech.
Introduction: Hayabusa space craft had brought backasteroid Itokawa particles to the Earth on June 2010. More than
1500 particles (composed of olivines, feldspars, Ca-pyroxenes,troilite, chromites, phosphates Fe-Ni metal grains, and othermaterials) were identified on the Qz glass after the compulsive
free fall, and most of them were very small ranging from 10 to300 µm but are mostly smaller than 50 µm [1-3]. In addtion
several amount of carbonaceous materials (Category 3 samples)
were found. Based on a FE-SEM with EDS observation at theJAXA curation facility, those materials mainly composed of C, N,
O and some of them contain NaCl and KCl [3].
Initial investigations of the returned rocky materials haveconfirmed that those are asteroidal samples by mineralogical andisotopical studies [1, 4]. Since Category 3 samples were notinvestigated precisely yet, we need to be clarified either terrestrial
or extraterrestrial material at first. Isotopic studies of H, C and N
for extraterrestrial organic materials in Stardust cometary
samples [5], IDPs [6], IOMs [7] and organic grobules [8] inprimitive chondrites played a key role to provide an evidence oforigin in the presolar molecular cloud or in the protoplanetary
disk. If we find the isotopic anomaries of H, C and N in Category
3 samples, these may be an extraterrestrial origin.
Here we report H, C and N isotopic measurement of organic
materials from Hayabusa Category 3 samples, RB-QD04-004702, RA-QD02-0120 and RB-QD04-0001. These samples werepressed on Au plate together with terrestrial standards of 1hydroxybenzotriazole hydrate and BBOT (C26H26N2O2S) withknown H, C and N isotopic compositions. Following the SEM
study to check the sample condition, the samples were analyzedfor H, C and N isotopic compositions by an isotopic imaging with
the JAMSTEC NanoSIMS 50L ion microprobe at Kochi Institutefor Core Sample Research.
Results: We evaluated isotopic analysis conditions by aNanoSIMS ion imaging through the measurements of terrestrail
standards, an organic material that corrected from the rocket
launch park at JAXA Tanegashima space center, IOM thatextraceted from A881458 meteorite [9].
Isotopic images of RB-QD04-0047-02, RA-QD02-0120 andRB-QD04-0001 have homogeneous H, C and N isotopic
composition. All samples had terrestrial H, C and N isotopic
compositions within error (δD = 60 ± 13 ‰, δ13C = 3 ± 3 ‰ andδ15N = -4 ± 2 ‰ for RB-QD04-0047-02; δD = 81 ± 54 ‰, δ13C =-20 ± 8 ‰ and δ15N = 2 ± 2 ‰ for RA-QD02-0120; δD = 135 ±32 ‰, δ13C = -20 ± 9 ‰ and δ15N = 16 ± 12 ‰ for RB-QD040001, 1σ). We continue to measure few more Category 3 samples
and will present isotopic data at the conference.
References: [1] Nakamura et al. 2011 Science 333:1113 [2]Tsuchiyama et al. 2011. Science 333:1125. [3] Hayabusa sample
catalogue:
http://hayabusaao.isas.jaxa.jp/catalog/cat3.
[4]
Yurimoto et al. 2011. Science 333:1116. [5] McKeegan et al.
2006. Science 314:1724. [6] Messenger 2000. Nature 404:968 [7]Busemann et al. 2006. Science 312:727. [8] NakamuraMessenger et al. 2006. Science 314:1439. [9] Oba and Naraoka.
2009. MaPS 44:943.