发表机构
Seoul National University; Korea Astronomy and Space Science Institute (KASI); National Astronomical Observatory of Japan（首尔大学; 韩国天文学与空间科学研究所; 日本国立天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究结合新观测与多波段数据，构建星际彗星3I/ATLAS的SED，发现其尘埃反照率约0.04、粒径指数3.0-3.3，虽偏振异常但物理性质与太阳系彗星一致。
AI 中文摘要
星际彗星3I/ATLAS与太阳系彗星相比表现出异常的偏振特性，而对其基本物理性质（如尘埃反照率和粒径分布）的约束仍然有限。我们利用Pirka望远镜在冲日附近获得了新的光学偏振测量数据，将其与先前报道的偏振测量结果相结合，并根据HST、VLT、SPHEREx和JWST的观测构建了可见光至中红外波段的光谱能量分布（SED）。SED表明彗发由暗色、吸收性尘埃主导，其有效V波段反照率约为$p_{\rm eff}\sim0.04$。使用幂律粒径分布对SED进行建模，得到粒径指数$q=3.0$--$3.3$。添加少量无定形硅酸盐成分可以更好地重现中红外光谱结构。综合偏振数据进一步支持高度多孔的散射结构。尽管其偏振行为异常，但3I/ATLAS尘埃的反照率和粒径分布处于太阳系彗星所观测到的范围之内。
英文摘要
The interstellar comet 3I/ATLAS exhibits unusual polarimetric properties compared with Solar System comets, while constraints on its fundamental physical properties, such as dust albedo and grain-size distribution, remain limited. We obtained new optical polarimetry near opposition with the Pirka Telescope, combined it with previously reported polarimetric measurements, and constructed a visible-to-mid-infrared spectral energy distribution (SED) from HST, VLT, SPHEREx, and JWST observations. The SED indicates that the coma is dominated by dark, absorbing dust, with an effective V-band albedo of $p_{\rm eff}\sim0.04$. Modeling the SED with a power-law grain-size distribution yields a size index of $q=3.0$--$3.3$. The mid-infrared spectral structure is better reproduced by adding a minor amorphous-silicate component. The combined polarimetric data further favor a highly porous scattering structure. Despite its unusual polarimetric behavior, the dust of 3I/ATLAS has an albedo and grain-size distribution within the range found for Solar System comets.
