[P-PS07] 太陽系物質進化

[PPS07-01] 炭素質隕石中ヘキサメチレンテトラミンの検出とその化学進化における役割

*大場 康弘¹、高野 淑識²、奈良岡 浩³、古川 善博⁴、橘 省吾^5,6、グラビン ダニエル⁷、ドワーキン ジェイソン⁷ (1.北海道大学低温科学研究所、2.海洋研究開発機構、3.九州大学、4.東北大学、5.東京大学、6.宇宙航空研究開発機構　宇宙科学研究所、7.アメリカ航空宇宙局　ゴダード宇宙飛行センター)

キーワード：ヘキサメチレンテトラミン、炭素質隕石、化学進化

Hexamethylenetetramine (HMT, C₆H₁₂N₄), an organic molecule with a characteristic cage-like structure, is the most abundant product in the photolysis of interstellar ice analogues containing water, methanol, ammonia, etc, under astrophysically relevant conditions. However, despite such properties, HMT has never been detected in any extraterrestrial environments/materials so far. We have for the first time detected HMT in three carbonaceous meteorites (Murchison, Tagish Lake, and Murray) whose concentrations are equivalent to other meteoritic organic molecules such as amino acids. Since HMT can yield formaldehyde and ammonia, which are necessary for the formation of various meteoritic organic molecules such as amino acids and sugars, upon (hydro)thermal degradations on meteorite parent bodies, it should play a vital role for chemical evolution in the solar system. In addition, the detected HMT would have formed by photochemical reactions in the interstellar medium, suggesting that its formation predated the formation of the solar system.

[Ref.] Oba, Y., Takano, Y., Naraoka, H., Furukawa, Y., Glavin, D.P., Dworkin, J.P. and Tachibana, S. (2020) Extraterrestrial hexamethylenetetramine in meteorites-a precursor of prebiotic chemistry in the inner solar system.
Nature Communications, 11, Article number: 6243. doi: 10.1038/s41467-020-20038-x.