van Kooten Elishevah, Zhao Xuchao, Franchi Ian, Tung Po-Yen, Fairclough Simon, Walmsley John, Onyett Isaac, Schiller Martin, Bizzarro Martin
Centre for Star and Planet Formation, Globe Institute, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark.
School of Physical Sciences, Open University, Milton Keynes, MK7 6AA, UK.
Sci Adv. 2024 Jun 14;10(24):eadp1613. doi: 10.1126/sciadv.adp1613.
Knowledge of the nucleosynthetic isotope composition of the outermost protoplanetary disk is critical to understand the formation and early dynamical evolution of the Solar System. We report the discovery of outer disk material preserved in a pristine meteorite based on its chemical composition, organic-rich petrology, and N-rich, deuterium-rich, and O-poor isotope signatures. We infer that this outer disk material originated in the comet-forming region. The nucleosynthetic Fe, Mg, Si, and Cr compositions of this material reveal that, contrary to current belief, the isotope signature of the comet-forming region is ubiquitous among outer Solar System bodies, possibly reflecting an important planetary building block in the outer Solar System. This nucleosynthetic component represents fresh material added to the outer disk by late accretion streamers connected to the ambient molecular cloud. Our results show that most Solar System carbonaceous asteroids accreted material from the comet-forming region, a signature lacking in the terrestrial planet region.
了解原行星盘最外层的核合成同位素组成对于理解太阳系的形成和早期动力学演化至关重要。我们基于一块原始陨石的化学成分、富含有机物的岩石学特征以及富含氮、富含氘和贫氧的同位素特征，报告了在外层盘中保存的物质的发现。我们推断这种外层盘物质起源于彗星形成区域。这种物质的核合成铁、镁、硅和铬组成表明，与当前的看法相反，彗星形成区域的同位素特征在太阳系外层天体中普遍存在，这可能反映了太阳系外层一个重要的行星构成要素。这种核合成成分代表了由与周围分子云相连的晚期吸积流束添加到外层盘的新鲜物质。我们的结果表明，大多数太阳系碳质小行星从彗星形成区域吸积了物质，而这是类地行星区域所缺乏的特征。
