Rosetta/OSIRIS observations of the 67P nucleus during the April 2016 flyby: high-resolution spectrophotometry
Rosetta/OSIRIS observations of the 67P nucleus during the April 2016 flyby: high-resolution spectrophotometry
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Rosetta/OSIRIS 在 2016 年 4 月飞越期间对 67P 核的观测：高分辨率分光光度法
DOI：
10.1051/0004-6361/201833807
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发表时间：
2018
影响因子：
6.5
通讯作者：
F. Scholten
中科院分区：
文献类型：
--
作者：
C. Feller;S. Fornasier;S. Ferrari;P. Hasselmann;A. Barucci;M. Massironi;J. Deshapriya;H. Sierks;G. Naletto;P. Lamy;R. Rodrigo;R. Rodrigo;D. Koschny;B. Davidsson;J. Bertaux;I. Bertini;D. Bodewits;G. Cremonese;V. Deppo;S. Debei;M. Cecco;M. Fulle;P. J. Guti'errez;C. Güttler;W. Ip;H. Keller;L. Lara;M. Lazzarin;J. Lopez‐Moreno;F. Marzari;Xian Shi;C. Tubiana;B. Gaskell;F. L. Forgia;A. Lucchetti;S. Mottola;M. Pajola;F. Preusker;F. Scholten
上下文。从2014年8月到2016年9月，罗塞塔号航天器沿着其轨道跟踪67P/丘留莫夫-格拉西缅科彗星。在彗星经过近日点后，罗塞塔于2016年4月在Imhotep-Khepry过渡上空进行了一次飞越操作。OSIRIS/窄角相机主要使用三个宽带滤光片(中心位于480、649和743 nm)，分辨率高达0.53m/px，相位角在0.095°和62°之间，获得了112次观测。
目标。我们利用OSIRIS/NAC的高分辨率观测资料研究了该地区的形态和光谱性质。
方法：研究方法。我们将观察结果组合成共同配准的颜色立方体。使用3D形状模型，我们为每个观测生成了照明条件和地理参考。我们绘制了过渡的观测地图，以调查其地貌。观测结果用朗梅尔-塞利格圆盘定律进行了光度校正。对配准后的色块进行分光光度分析。这些数据被用来估计局部相位变红。
结果。Imhotep-Khepry过渡地区拥有众多不同类型的地形和特征。我们观察到特征的性质、其反射率和其光谱斜率之间的关联。细粒物质沉积表现出平均反射率和光谱斜率，而具有直径、固结物质、退化露头或暗色巨石等特征的地形则表现出低于平均反射率和高于平均光谱斜率。明亮的表面呈现出与富含水冰的地形相一致的光谱行为。我们发现2.7Au出站时的位相变红斜率为0.064±0.001%/0.001 nm/°，与2015年2月飞越2.3Au入站时的红化斜率相似。
结论。Imhotep-Khepry过渡被确定为多个喷流和大量水冰物质的源区，出现在2016年4月，靠近霜冻线，在其众多不同的地形单元中，进一步隐藏了几个可能有暴露的水冰物质的地点。
Context. From August 2014 to September 2016, the Rosetta spacecraft followed comet 67P/Churyumov–Gerasimenko along its orbit. After the comet passed perihelion, Rosetta performed a flyby manoeuvre over the Imhotep–Khepry transition in April 2016. The OSIRIS/Narrow-Angle-Camera (NAC) acquired 112 observations with mainly three broadband filters (centered at 480, 649, and 743 nm) at a resolution of up to 0.53 m/px and for phase angles between 0.095° and 62°.
Aims. We have investigated the morphological and spectrophotometrical properties of this area using the OSIRIS/NAC high-resolution observations.
Methods. We assembled the observations into coregistered color cubes. Using a 3D shape model, we produced the illumination conditions and georeference for each observation. We mapped the observations of the transition to investigate its geomorphology. Observations were photometrically corrected using the Lommel–Seeliger disk law. Spectrophotometric analyses were performed on the coregistered color cubes. These data were used to estimate the local phase reddening.
Results. The Imhotep–Khepry transition hosts numerous and varied types of terrains and features. We observe an association between a feature’s nature, its reflectance, and its spectral slopes. Fine material deposits exhibit an average reflectance and spectral slope, while terrains with diamictons, consolidated material, degraded outcrops, or features such as somber boulders present a lower-than-average reflectance and higher-than-average spectral slope. Bright surfaces present here a spectral behavior consistent with terrains enriched in water-ice. We find a phase-reddening slope of 0.064 ± 0.001%/100 nm/° at 2.7 au outbound, similar to the one obtained at 2.3 au inbound during the February 2015 flyby.
Conclusions. Identified as the source region of multiple jets and a host of water-ice material, the Imhotep–Khepry transition appeared in April 2016, close to the frost line, to further harbor several potential locations with exposed water-ice material among its numerous different morphological terrain units.
影响因子：
3.2
作者：
Kaufmann E
通讯作者：
Kaufmann E