AI 中文总结
该研究通过JWST观测周期性爆发原恒星EC 53，发现吸积爆发时内盘原位形成结晶硅酸盐，嵌套外流可输送其向外，为早期恒星尘埃处理与再分布提供首个直接观测证据。
AI 中文摘要
结晶硅酸盐在高温（>900 K；Fabian等人2000年；Hallenbeck等人1998年）下形成，其在彗星中的存在（Hanner等人1994年；Hayward等人2000年；Wooden等人2002年；Shinnaka等人2018年）表明早期太阳系中发生了高温尘埃处理，随后被向外输送到彗星形成区域。然而，类太阳原恒星中这种结晶和再分布的直接证据一直难以获得。通过比较詹姆斯·韦布空间望远镜（JWST）对周期性爆发原恒星EC 53（Lee等人2020年）的中红外光谱，我们检测到仅在爆发期间出现的结晶硅酸盐（镁橄榄石和顽火辉石）发射特征。这些特征的出现表明，在吸积爆发期间，热内盘中通过热退火发生活跃的晶体形成。我们还检测到嵌套外流——由较慢的分子外流包裹的准直原子喷流，这与磁流体动力学（MHD）风模型（Pascucci等人2025年）一致。这种结构为新形成的结晶硅酸盐的向外输送提供了机制（Giacalone等人2019年）。我们的结果提供了一个仍嵌在致密包层中的极年轻恒星在间歇性吸积爆发期间原位硅酸盐结晶的首个直接观测证据。尽管我们未直接检测到被输送到外盘的颗粒，但观测到的趋势与向外再分布一致，表明在恒星形成最早且最活跃的阶段，尘埃处理和输送均会发生。
英文摘要
Crystalline silicates form at high temperatures (> 900 K; Fabian et al. 2000; Hallenbeck et al. 1998). Their presence in comets (Hanner et al. 1994; Hayward et al. 2000; Wooden et al. 2002; Shinnaka et al. 2018) suggests that high-temperature dust processing occurred in the early Solar System and was subsequently transported outward to comet-forming regions. However, direct evidence for this crystallization and redistribution in Sun-like protostars has remained elusive. By comparing James Webb Space Telescope (JWST) mid-infrared spectra of the periodically bursting protostar EC 53 (Lee et al. 2020), we detect crystalline silicate (forsterite and enstatite) emission features that appear only during the burst. The emergence of these features indicates active crystal formation via thermal annealing in the hot inner disk during the accretion burst. We also detect a nested outflow-a collimated atomic jet enclosed by slower molecular outflows, consistent with magnetohydrodynamic (MHD) wind models (Pascucci et al. 2025). This configuration provides a mechanism for outward transport of freshly crystallized silicates (Giacalone et al. 2019). Our results provide the first direct observational evidence of in-situ silicate crystallization during episodic accretion bursts in a very young star still embedded in its dense envelope. Although we do not directly detect grains transported to the outer disk, the observed trends are consistent with outward redistribution, indicating that both dust processing and transport occur during the earliest and most dynamic stages of star formation.
Comments33 pages, 12 figures, 1 table, This is the author accepted manuscript of an article published in Nature. The final published version is available at this https URL (https://www.nature.com/articles/s41586-025-09939-3)
Journal refNature 649, 853-858 (2026)
DOI：10.1038/s41586-025-09939-3
