美国约翰斯·霍普金斯大学Chen Xie团队揭示了HD 181327周围的碎片盘中有水冰。相关论文于2025年5月14日发表在《自然》杂志上。

碎片盘是包含行星、小行星（小行星、柯伊伯带天体、彗星等）和微米级碎片尘埃的系外行星系统。因为水冰是最常见的冷冻挥发性物质，它在行星和小行星的形成中起着至关重要的作用。尽管在太阳系的柯伊伯带天体和彗星中经常发现水冰，但迄今为止还没有获得碎片盘中存在水冰的明确证据。 

研究组报告了使用詹姆斯·韦伯太空望远镜上的近红外光谱仪在HD 181327碎片盘中发现的水冰。他们在3 µm时检测到水冰的固态宽吸收特征，包括3.1 µm处的明显菲涅耳峰，这表示大的结晶水冰颗粒。水冰特征中的梯度作为星心距离的函数，揭示了水冰被破坏和补充的动态环境。

研究组估计水冰质量分数在0.1%左右、约为85 au降至21%、约为113 au表示在雪线之外的HD 181327盘中存在水冰储库。HD 181327中释放水冰的冰体可能是太阳系中富含水冰的柯伊伯带天体的太阳系外对应物。

附：英文原文

Title: Water ice in the debris disk around HD 181327

Author: Xie, Chen, Chen, Christine H., Lisse, Carey M., Hines, Dean C., Beck, Tracy, Betti, Sarah K., Pinilla-Alonso, Noem, Ingebretsen, Carl, Worthen, Kadin, Gspr, Andrs, Wolff, Schuyler G., Bolin, Bryce T., Pueyo, Laurent, Perrin, Marshall D., Stansberry, John A., Leisenring, Jarron M.

Issue&Volume: 2025-05-14

Abstract: Debris disks are exoplanetary systems that contain planets, minor bodies (asteroids, Kuiper belt objects, comets and so on) and micrometre-sized debris dust1. Because water ice is the most common frozen volatile, it plays an essential role in the formation of planets2,3 and minor bodies. Although water ice has been commonly found in Kuiper belt objects and comets in the Solar System4, no definitive evidence for water ice in debris disks has been obtained to date1. Here we report the discovery of water ice in the HD 181327 debris disk using the near-infrared spectrograph onboard the James Webb Space Telescope. We detected the solid-state broad absorption feature of water ice at 3μm including a distinct Fresnel peak at 3.1μm, which is indicative of large, crystalline water-ice particles. Gradients in the water-ice feature as a function of stellocentric distance reveal a dynamic environment in which water ice is destroyed and replenished. We estimated the water-ice mass fractions as ranging from 0.1% at approximately 85au to 21% at approximately 113au, indicating the presence of a water-ice reservoir in the HD 181327 disk beyond the snow line. The icy bodies that release water ice in HD 181327 are probably the extra-solar counterparts of water-ice-rich Kuiper belt objects in our Solar System.

DOI: 10.1038/s41586-025-08920-4

Source: https://www.nature.com/articles/s41586-025-08920-4