近日，韩国首尔大学Jeong-Eun Lee团队报道了行星形成盘中的吸积爆发硅酸盐结晶。相关论文于2026年1月21日发表在《自然》杂志上。

结晶硅酸盐在高温条件下（>900 K）形成，其在彗星中的存在表明，在早期太阳系中曾发生过高温尘埃的加工过程，随后被向外输送至形成彗星的区域。然而，关于类太阳原恒星中这种结晶和再分布仍缺乏直接证据。

通过对比詹姆斯·韦伯空间望远镜对周期性爆发的原恒星EC 53所获取的中红外光谱，研究组发现了只有在爆发期间才会出现的结晶硅酸盐（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，高温内部盘中通过热退火作用形成了活跃晶体。

研究组还探测到一个嵌套式的外流，即一条被较慢分子外流包围的准直原子射流，这与磁流体动力学风模型的演示一致。这种结构提供了一种新型结晶硅酸盐向外运输的机制。该结果首次报道了在一颗仍嵌入其致密外层包裹之中的极年轻恒星中，在周期性吸积爆发期间进行硅酸盐结晶的直接观测证据。虽然研究组无法直接观测到物质颗粒被输送到外盘，但所观察到的趋势与向外重新分布保持一致，这表明尘埃处理和外输过程发生在恒星形成的最初且最为活跃的阶段。

附：英文原文

Title: Accretion bursts crystallize silicates in a planet-forming disk

Author: Lee, Jeong-Eun, Kim, Chul-Hwan, Kim, Jaeyeong, Lee, Seokho, Kim, Young-Jun, Lee, Seonjae, Baek, Giseon, Green, Joel D., Herczeg, Gregory J., Johnstone, Doug, Pontoppidan, Klaus M., Aikawa, Yuri, Yang, Yao-Lun, Francis, Logan, Jin, Mihwa, Jang, Hyerin

Issue&Volume: 2026-01-21

Abstract: Crystalline silicates form at high temperatures (>900K) (refs.1,2). Their presence in comets3,4,5,6 suggests that high-temperature dust processing occurred in the early Solar System and was subsequently transported outwards to comet-forming regions. However, direct evidence for this crystallization and redistribution in Sun-like protostars has remained unknown. By comparing James Webb Space Telescope mid-infrared spectra of the periodically bursting protostar EC 53 (ref.7), we detect crystalline silicate (forsterite and enstatite) emission features that appear only during the burst. The emergence of these features indicates active crystal formation by 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 wind models8. This configuration provides a mechanism for the outward transport of freshly crystallized silicates9. To our knowledge, 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.

DOI: 10.1038/s41586-025-09939-3

Source: https://www.nature.com/articles/s41586-025-09939-3