论文标题
H $ {} _ {2} $ o冰的晶粒尺寸估计中的差异在外部太阳系和星际介质中
Discrepancy in Grain Size Estimation of H${}_{2}$O Ice in the Outer Solar System and the Interstellar Medium
论文作者
论文摘要
在过去的几十年中，已经确认了外部太阳系体和星际介质中的无定形和结晶水（H $ {} _ {2} $ O）冰的广泛检测。辐射转移模型（RTMS）用于估计来自近红外（NIR）波长的H $ {} _ {2} $ o冰的晶粒大小。估计H $ {} _ {2} $ O冰粒大小（Hansen，2009年）以及氮气（N $ {} _ {2} $）和甲烷（ch $ {} _ {4} _ {4} $ contried at em emrand at em n. 2022）。我们在15、40、60和80 K（无定形）和20、40、60、60和80 K（结晶）的温度下，评估了H $ {} _冰的晶粒大小估计的差异。我们使用MIE理论（MIE，1908）和HAPKE近似模型（Hapke，1993）比较了H $ {} _ {} _ {2} $ o冰阶段的单个散射反照率。这项研究表明，HAPKE近似模型 - HAPKE平板和内部散射模型（ISM） - 预测晶体相的晶粒尺寸，总的来说，与15-80 K的温度下的无定形相比，它要好得多。但是，HAPKE SLAB模型估计MIE模型的预测更高，估计MIE模型的预测更高的谷物尺寸，估计差异很大。我们建议将MIE模型用于估计h $ {} _ {2} $ o冰粒尺寸的外部太阳系物体及以后的未知光谱。在选择用于使用RTM的近似模型的同时，我们建议在内部散射模型上使用HAPKE平板近似模型。
Widespread detection of amorphous and crystalline water (H${}_{2}$O) ice in the outer solar system bodies and the interstellar medium has been confirmed over the past decades. Radiative transfer models (RTMs) are used to estimate the grain sizes of H${}_{2}$O ice from near-infrared (NIR) wavelengths. Wide discrepancies in the estimation of H${}_{2}$O ice grain size on the Saturnian moons (Hansen, 2009), as well as nitrogen (N${}_{2}$) and methane (CH${}_{4}$) ices on Kuiper belt objects have been reported owing to different scattering models used (Emran and Chevrier, 2022). We assess the discrepancy in the grain size estimation of H${}_{2}$O ice at a temperature of 15, 40, 60, and 80 K (amorphous) and 20, 40, 60, and 80 K (crystalline) - relevant to the outer solar system and beyond. We compare the single scattering albedos of H${}_{2}$O ice phases using the Mie theory (Mie, 1908) and Hapke approximation models (Hapke, 1993) from the optical constant at NIR wavelengths (1 - 5 $μ$m). This study reveals that the Hapke approximation models - Hapke slab and internal scattering model (ISM) - predict grain size of the crystalline phase, overall, much better compared to the amorphous phase at temperatures of 15 - 80 K. However, the Hapke slab model estimates much approximate grain sizes, in general, to that of the Mie model's prediction while ISM exhibits a higher uncertainty. We recommend using the Mie model for unknown spectra of outer solar system bodies and beyond in estimating H${}_{2}$O ice grain sizes. While choosing the approximation model for employing RTMs, we recommend using a Hapke slab approximation model over the internal scattering model.
