论文标题
天王星五个主要月亮的Herschel-Pacs光度法
Herschel-PACS photometry of Uranus' five major moons
论文作者
论文摘要
目标。我们旨在根据赫尔舍尔空间天文台观察到的观测值，以70、100和160美元的五个主要天王星卫星钛二氧化钛，Oberon，Umbriel，Ariel和Miranda确定远红外通量。 方法。使用从每个波长的所有图中建立的迭代过程中的所有地图上建立的缩放的天王星点扩散函数（PSF）参考来减去天王星的明亮图像，从而消除了叠加的月亮。卫星的光度法由PSF光度法执行。冰冷月亮的热物理模型适合每个测量时期的光度法和较短波长的辅助数据的光度法。 结果。最好的拟合热物理模型为卫星的重要热特性提供了约束，例如表面粗糙度和热惯性。我们在带有赤道照明时期，提出了第一个5 $ $ m $ m $ m $ m $ m $ m的热红外辐射测定法长度为50 $ m $ m。由于这种倾斜的几何形状，夜间有热传输，因此热惯性发挥了作用，使我们能够约束该参数。还发现了一些指示，表明铅和后半球的热性能差异。当将天王星用作远红外的Prime通量校准器时，我们精确地指定了天王星通量的系统误差。 结论。我们已经成功地展示了PACS光度计数据的图像处理技术，从而可以删除明亮的中央源。我们已经建立了改进的五个主要天王星卫星的热物理模型。衍生的热惯性值比较小的tnos和centAurs的热惯性值类似于TNO矮行星冥王星和Haumea的惯性值。
Aims. We aim to determine far-infrared fluxes at 70, 100, and 160$μ$m of the five major Uranus satellites Titania, Oberon, Umbriel, Ariel and Miranda, based on observations with the photometer PACS-P aboard the Herschel Space Observatory. Methods. The bright image of Uranus is subtracted using a scaled Uranus point spread function (PSF) reference established from all maps of each wavelength in an iterative process removing the superimposed moons. Photometry of the satellites is performed by PSF photometry. Thermophysical models of the icy moons are fitted to the photometry of each measurement epoch and auxilliary data at shorter wavelengths. Results. The best fitting thermophysical models provide constraints for important thermal properties of the moons like surface roughness and thermal inertia. We present the first thermal infrared radiometry longward of 50$μ$m of the four largest Uranian moons, Titania, Oberon, Umbriel and Ariel, at epochs with equator-on illumination. Due to this inclination geometry there was heat transport to the night side so that thermal inertia played a role, allowing us to constrain that parameter. Also some indication for differences in the thermal properties of leading and trailing hemispheres is found. We specify precisely the systematic error of the Uranus flux by its moons, when using Uranus as a far-infrared prime flux calibrator. Conclusions. We have successfully demonstrated an image processing technique for PACS photometer data allowing to remove a bright central source. We have established improved thermophysical models of the five major Uranus satellites. Derived thermal inertia values resemble more those of TNO dwarf planets Pluto and Haumea than those of smaller TNOs and Centaurs.
