TY - JOUR
T1 - The Earth atmosphere-like bulk nitrogen isotope composition obtained by stepwise combustion analyses of Ryugu return samples
AU - the Hayabusa2 Initial Analysis Volatile Team
AU - Hashizume, Ko
AU - Ishida, Akizumi
AU - Chiba, Ayano
AU - Okazaki, Ryuji
AU - Yogata, Kasumi
AU - Yada, Toru
AU - Kitajima, Fumio
AU - Yurimoto, Hisayoshi
AU - Nakamura, Tomoki
AU - Noguchi, Takaaki
AU - Yabuta, Hikaru
AU - Naraoka, Hiroshi
AU - Takano, Yoshinori
AU - Sakamoto, Kanako
AU - Tachibana, Shogo
AU - Nishimura, Masahiro
AU - Nakato, Aiko
AU - Miyazaki, Akiko
AU - Abe, Masanao
AU - Okada, Tatsuaki
AU - Usui, Tomohiro
AU - Yoshikawa, Makoto
AU - Saiki, Takanao
AU - Terui, Fuyuto
AU - Tanaka, Satoshi
AU - Nakazawa, Satoru
AU - Watanabe, Sei ichiro
AU - Tsuda, Yuichi
AU - Broadley, Michael W.
AU - Busemann, Henner
N1 - Publisher Copyright:
© 2024 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society.
PY - 2024/8
Y1 - 2024/8
N2 - The nitrogen isotope compositions of two samples returned from the asteroid Ryugu were determined using a stepwise combustion method, along with Ivuna (CI) and Y-980115, a CI-like Antarctic meteorite, as references. The two Ryugu samples A0105-07 and C0106-07 showed bulk δ15N values of +1.7 ± 0.5‰ and +0.2 ± 0.6‰, respectively, significantly lower than Ivuna with +36.4 ± 0.4‰, but close to Y-980115 with +4.0 ± 0.3‰. The Ryugu samples are further characterized by C/N and 36Ar/N ratios up to 3.4× and 4.9× the value of Ivuna, respectively. Among all Ryugu samples and CI chondrites, a positive correlation was observed between nitrogen concentrations and δ15N values, with samples with lower nitrogen concentrations exhibiting lower δ15N. This trend is explained by a two-component mixing model. One component is present at a constant abundance among all CI-related samples, with a δ15N value around 0‰ or lower. The other varies in abundance between different samples, and exhibits a δ15N value of +56 ± 4‰. The first 15N-poor endmember is seemingly tightly incorporated into a carbonaceous host phase, whereas the 15N-rich endmember can be mobilized and decoupled from carbon, potentially because it is in the form of ammonia. Asteroid materials with volatile compositions that are similar to those reported here for the Ryugu samples are attractive candidates for the volatile sources among Earth's building blocks.
AB - The nitrogen isotope compositions of two samples returned from the asteroid Ryugu were determined using a stepwise combustion method, along with Ivuna (CI) and Y-980115, a CI-like Antarctic meteorite, as references. The two Ryugu samples A0105-07 and C0106-07 showed bulk δ15N values of +1.7 ± 0.5‰ and +0.2 ± 0.6‰, respectively, significantly lower than Ivuna with +36.4 ± 0.4‰, but close to Y-980115 with +4.0 ± 0.3‰. The Ryugu samples are further characterized by C/N and 36Ar/N ratios up to 3.4× and 4.9× the value of Ivuna, respectively. Among all Ryugu samples and CI chondrites, a positive correlation was observed between nitrogen concentrations and δ15N values, with samples with lower nitrogen concentrations exhibiting lower δ15N. This trend is explained by a two-component mixing model. One component is present at a constant abundance among all CI-related samples, with a δ15N value around 0‰ or lower. The other varies in abundance between different samples, and exhibits a δ15N value of +56 ± 4‰. The first 15N-poor endmember is seemingly tightly incorporated into a carbonaceous host phase, whereas the 15N-rich endmember can be mobilized and decoupled from carbon, potentially because it is in the form of ammonia. Asteroid materials with volatile compositions that are similar to those reported here for the Ryugu samples are attractive candidates for the volatile sources among Earth's building blocks.
UR - http://www.scopus.com/inward/record.url?scp=85192208185&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85192208185&partnerID=8YFLogxK
U2 - 10.1111/maps.14175
DO - 10.1111/maps.14175
M3 - Article
AN - SCOPUS:85192208185
SN - 1086-9379
VL - 59
SP - 2117
EP - 2133
JO - Meteoritics and Planetary Science
JF - Meteoritics and Planetary Science
IS - 8
ER -