Polycyclic aromatic hydrocarbons in samples of Ryugu formed in the interstellar medium

• DOI: 10.1126/science.adg6304
• Publication Date: 2023-12-21T19:03:38Z
• Authors: Sarah S. Zeichner; José C. Aponte; Surjyendu Bhattac...; 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 Or...; Véronique Vuitton; Cédric Wolters; Philippe Schmitt-...; 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. No...; Kazunori Sasaki; Hajime Sato; Takaaki Yoshikawa; Satoru Tanaka; Mayu Morita; Morihiko Onose; Fumie Kabashima; Kosuke Fujishima; Tomoya Yamazaki; Yuki Kimura; John M. Eiler
• Keywords: Fluoranthene; Murchison meteorite; Carbonaceous chondrite; Polycyclic aromatic hydrocarbon; Carbon fibers

Polycyclic aromatic hydrocarbons (PAHs) contain ≲20% of the carbon in interstellar medium. They are potentially produced circumstellar environments (at temperatures ≳1000 kelvin), by reactions within cold (~10 kelvin) clouds, or processing carbon-rich dust grains. We report isotopic properties PAHs extracted from samples asteroid Ryugu and meteorite Murchison. The doubly-13C substituted compositions (Δ2×13C values) naphthalene, fluoranthene, pyrene 9 to 51‰ higher than values expected for a stochastic distribution isotopes. Δ2×13C if formed environment, but consistent with formation By contrast, phenanthrene anthracene have higher-temperature reactions.