论文标题

Philae着陆点和周围环境的分光光度特征与Rosetta/Osiris摄像机

Spectrophotometric characterization of the Philae landing site and surroundings with the ROSETTA/OSIRIS cameras

论文作者

Van Hoang, Hong, Fornasier, S., Quirico, E., Hasselmann, P. H., Barucci, M. A., Sierks, H., Tubiana, C., Güttler, C.

论文摘要

我们调查了阿比多斯(Abydos),这是Philae Lander的最终着陆地点,该地点是2014年11月12日从Rosetta Spacecraft上从Rosetta Spacecraft上登陆的67p/Churyumov-Gerasimenko。在2014年8月至2014年9月至2014年9月的时间段内,分析了1000次Osiris 3B级图像。我们发现Abydos位点与全局67p核和频谱红色一样暗,在649 nm时的平均反照率为6.5%,光谱斜率值约为17%/(100 nm),在50 $^\ circ $相位角度。与整个核类似,Abydos位点还显示出相红化,但系数低于彗星的其他区域,这可能意味着与其他区域相比,显微镜粗糙的岩石覆盖物。还观察到了整个核的季节变化,也观察到了。我们确定了着陆点附近的一些潜在形态变化,这意味着总质量损失为4.7-7.0 $ \ times $ 10 $^5 $ kg。在周围和之后,观察到靠近Abydos的小点,从0.1 m $^2 $到27 m $^2 $。他们估计的水冰丰度在本地达到30-40%,表明挥发物的新鲜暴露。他们的终生范围从几个小时到三个月的临时景点。与核的其他区域相比,ABYDOS周围的彗星活性水平较低。据报道,只有几架喷气机起源于附近的阿比多斯,其中包括持续了大约一个小时的明亮爆发。

We investigate Abydos, the final landing site of the Philae lander after its eventful landing from the Rosetta spacecraft on comet 67P/Churyumov-Gerasimenko on 12 November 2014. Over 1000 OSIRIS level 3B images were analysed, which cover the August 2014 to September 2016 timeframe, with spatial resolution ranging from 7.6 m/px to approximately 0.06 m/px. We found that the Abydos site is as dark as the global 67P nucleus and spectrally red, with an average albedo of 6.5% at 649 nm and a spectral slope value of about 17%/(100 nm) at 50$^\circ$ phase angle. Similar to the whole nucleus, the Abydos site also shows phase reddening but with lower coefficients than other regions of the comet which may imply a thinner cover of microscopically rough regolith compared to other areas. Seasonal variations, as already noticed for the whole nucleus, were also observed. We identified some potential morphological changes near the landing site implying a total mass loss of 4.7-7.0$\times$10$^5$ kg. Small spots ranging from 0.1 m$^2$ to 27 m$^2$ were observed close to Abydos before and after perihelion. Their estimated water ice abundance reaches 30-40% locally, indicating fresh exposures of volatiles. Their lifetime ranges from a few hours up to three months for two pre-perihelion spots. The Abydos surroundings showed low level of cometary activity compared to other regions of the nucleus. Only a few jets are reported originating nearby Abydos, including a bright outburst that lasted for about one hour.

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