该研究报道了小行星Ryugu和陨石Murchison的样品中提取的多环芳烃的同位素性质。多环芳烃萘、荧蒽和嵌二萘的双-13C取代成分（Δ 2×13C ）比同位素随机分布预期值高9-15‰。如果多环芳烃形成于星周环境，Δ 2×13C值就会高于预期，但与星际介质中的形成一致。相比之下，Ryugu样品中多环芳烃菲和蒽的Δ 2×13C值与高温反应形成的结果一致。
据介绍，多环芳烃(PAHs)含有星际介质中碳小于约等于20％。它们可能产生于星周环境（温度大于约等于1,000开尔文），由星际云（温度约为10开尔文）产生，或者由富含碳的尘埃颗粒转变而成。
附：英文原文
Title: Polycyclic aromatic hydrocarbons in samples of Ryugu formed in the interstellar medium
Author: Sarah S. Zeichner, José C. Aponte, Surjyendu Bhattacharjee, Guannan Dong, Amy E. Hofmann, Jason P. Dworkin, Daniel P. Glavin, Jamie E. Elsila, Heather V. Graham, Hiroshi Naraoka, Yoshinori Takano, Shogo Tachibana, Allison T. Karp, Kliti Grice, Alex I. Holman, Katherine H. Freeman, Hisayoshi Yurimoto, Tomoki Nakamura, Takaaki Noguchi, Ryuji Okazaki, Hikaru Yabuta, Kanako Sakamoto, Toru Yada, Masahiro Nishimura, Aiko Nakato, Akiko Miyazaki, Kasumi Yogata, Masanao Abe, Tatsuaki Okada, Tomohiro Usui, Makoto Yoshikawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Sei-ichiro Watanabe, Yuichi Tsuda, Kenji Hamase, Kazuhiko Fukushima, Dan Aoki, Minako Hashiguchi, Hajime Mita, Yoshito Chikaraishi, Naohiko Ohkouchi, Nanako O. Ogawa, Saburo Sakai, Eric T. Parker, Hannah L. McLain, Francois-Regis Orthous-Daunay, Véronique Vuitton, Cédric Wolters, Philippe Schmitt-Kopplin, Norbert Hertkorn, Roland Thissen, Alexander Ruf, Junko Isa, Yasuhiro Oba, Toshiki Koga, Toshihiro Yoshimura, Daisuke Araoka, Haruna Sugahara, Aogu Furusho, Yoshihiro Furukawa, Junken Aoki, Kuniyuki Kano, Shin-ichiro M. Nomura, Kazunori Sasaki, Hajime Sato, Takaaki Yoshikawa, Satoru Tanaka, Mayu Morita, Morihiko Onose, Fumie Kabashima, Kosuke Fujishima, Tomoya Yamazaki, Yuki Kimura, John M. Eiler
Issue&Volume: 2023-12-22
Abstract: Polycyclic aromatic hydrocarbons (PAHs) contain 20% of the carbon in the interstellar medium. They are potentially produced in circumstellar environments (at temperatures 1000 kelvin), by (~10 kelvin) interstellar clouds, or by processing of carbon-rich dust grains. We report isotopic properties of PAHs extracted from samples of the asteroid Ryugu and the meteorite Murchison. The doubly-13C substituted compositions (Δ 2×13C values) of the PAHs naphthalene, fluoranthene, and pyrene are 9 to 51‰ higher than values expected for a stochastic distribution of isotopes. The Δ 2×13C values are higher than expected if the PAHs formed in a circumstellar environment, but consistent with formation in the interstellar medium. By contrast, the PAHs phenanthrene and anthracene in Ryugu samples have Δ 2×13C values consistent with formation by higher-temperature reactions.
DOI: adg6304
Source: https://www.science.org/doi/10.1126/science.adg6304